Dice Mechanics

I originally wrote this before the series on a 2d10 RPG, but I thought it was interesting for different reasons. And it's still true, even if I've settled on what I personally like.

I’ve been thinking a lot about table-top RPG mechanics recently. There are a lot of different ones used, including roll-under, roll-over, dice pool, and various combinations. For the moment, I’ll stick with dice mechanics, and try to discuss the various pros-and-cons.

Why dice?

The first question to ask is why are there dice? Why do role-playing games favor random dice rolls at all? It’s a useful question to ask. Dice exist to turn collaborative story-telling into a game, letting an objective arbiter (the dice) decide whether the player (including, sometimes, the DM) succeeds or fails. It also adds risk/reward to allow the player to attempt something where it’s not guaranteed that he’ll succeed.

It is possible to have a role-playing game without dice. Sometimes an alternative source of randomness can be used (such as cards), and sometimes no randomness is used at all. In that case, players succeed or fail depending on their stats, and random chance doesn’t enter into it. In some ways, videogame JRPGs often depend much more on the player and monster stats than any random numbers (attacks almost always hit, damage is always within a certain range), and overcoming non-monster obstacles depend much more on player observational skills than any random number generation.

But a lot of that is that computer algorithms can, in their complexity, give the appearance of randomness. It’s hard to predict what will happen because the systems are hidden from us, and even when they aren’t, they’re beyond our capacity to calculate quickly. Whereas, in table-top RPGs, we want to keep the complexity of the calculation simple and the systems up-front, so we allow dice to create the risk.

There are a number of different dice systems used in TTRPGs, but they can usually be categorized in the following ways.

Flat roll-over

Let’s start with a single die. You roll that die, add a number based on your character’s stats, and check against a target number to see if you succeed. The die is assumed to have flat probability distribution. On a 20-sided die, you are as likely to roll a 1, or a 7, or an 11, or a 20. In this system it’s easy to figure out what the probabilities are. Let’s say you have a +3 on the roll and you need a 15. A 12 or higher will succeed, so you have a 45% chance of success. The difficulty can be adjusted by changing the target number. In Dungeons and Dragon, the target number is set by the DM, and represents the difficulty of the task. However, there are other systems that are still flat roll-over systems.

Let’s take the Against the Darkmaster system. VsD uses a d100 roll (this technically uses two dice, but since it still gives a flat probability distribution, it’s equivalent to a single die). In most circumstances, the target number is fixed at 100, which means that the probability of success is the same as your bonus (a  +30 bonus means you have a 30% probability of success). Difficulty is determined by adding a penalty to the roll.

Flat roll-under

The converse of the roll-over system is the roll-under system. This works very similarly to the above, except that you need to roll under a value. In this case, the value is usually dependent on your skill. For example, Call of Cthulhu and Warhammer Fantasy RPG both use a d100 roll-under system, where your skill rating is the value you need to roll under. If you have a 33 in a skill, you need to roll 33 or under. The GM can adjust the difficulty by adding or subtracting from the target number. For example, a routine check in WFRPG adds 20 to your skill rating and requires you to roll under that (so 53 for that skill you have 33 in).

The advantage of the single die roll-over and roll-under is that it’s easy to figure out the probabilities. Both for players (how likely am I to succeed if I attempt this?), and for the GM (how hard should I make this if I want the player to be likely to succeed, but not guaranteed?). In this respect, Call of Cthulhu and Warhammer are the easiest—you’re told the number you’re trying to beat before you make the roll. But you don’t always want players to know exactly what they need. D&D allows the DM to obscure this number by simply not telling the players the target number they’re trying to reach.

Note that in both roll-over and roll-under, the higher the number on the character sheet, the more likely it is for the player to succeed on that task. This is in general good game design. Higher numbers being better is intuitive for players.

However, one issue with both flat probability distribution systems is how swingy it is. The 20-sided die, or the d100 dice, give a much wider range of possible rolls than the typical player character bonus. One way to address this, often explicitly stated in books, is not to require rolls unless the situation calls for it. For someone trained to ride a horse, most of the time he just rides the horse. But if the horse is spooked by something, or he’s trying to win a horserace, or running from the Wild Hunt, in that case, he should roll for it.

The issue is that in most games, there’s no difference between someone trained in a skill and untrained unless you roll a die. And when you do roll dice, the swinginess means that success or failure depends more on the roll of the dice than your skill or training.

Summing dice pool

This has some of the advantages of the single-die roll-over, but adds the complexity of multiple dice, which makes it very hard for players and the DM to calculate the odds on the fly. Take the 3d6 roll. This is a binomial probability distribution peaked around 10 and 11. 67% of the time, this number is going to be somewhere in the range of 8 through 13. What this means is that numbers outside of that range are very unlikely. There’s only about 0.5% chance of rolling a 3, and a 0.5% chance of rolling an 18. For people who want most dice rolls to fall in a predictable range—who want something less swingy than D&D—this is reassuring. Games like HERO and GURPS use a roll-under version of this system (your stats set the target number you’re trying to roll under), while games like AGE use a roll-over version of this system (your stats set the bonus, and the GM determines the target number). I worry that it’s easy to mess up in this system. A +1 or +2 to either the bonus or the difficulty can have a significant effect on the probability, and it’s easy for the GM to set target numbers that seem reasonable but are practically impossible.

This system probably works better when it isn’t quite so sharply peaked. A more reasonable version is the 2d6 system used in Powered by the Apocalypse, a system used in a number of games, including Apocalypse World, Dungeon World, Monster of the Week, and Avatar: The Last Airbender RPG. In this system, rolling less than a 7 is a failure, 7-9 is a success with a complication, and 10+ is a full success. Player stats give them somewhere between a -1 and a +3 modifier, and the GM can determine that the situation gives them a penalty or a bonus. While this isn’t as sharply peaked as 3d6, you still have a 58% chance to roll a 7 or higher, and a +3 means that you’re more likely than not to roll a complete success.

Usually the number of dice you roll in a summing dice pool is fixed, but some systems allow you to roll more depending on your character stats. This can lead to huge differentials between skilled and unskilled characters. The One Ring uses a version of this, but its mechanics make this less of a problem than something like West End Games’ old Star Wars RPG, which often saw a huge difference between normal and Force-using characters due to using this mechanic. Arguably this was the desired effect, but it messed with game balance.

Counting dice pool

In this system, you roll a number of dice and count the number which meet a requirement, the number of sixes, or above a certain value.

This system has a number of advantages. The first is that it’s generally easier for players to roll a bunch of dice and on-the-fly count the number of sixes than to add up all the numbers on the dice. Also, it’s generally easier to figure out the odds of success or failure than for a summing dice pool, though not as easy as for a flat roll-over or roll-under system.

Systems based on this include the World of Darkness games (Vampire the Masquerade, Mage the Ascension, etc.) and Shadowrun. What these games have in common is needing a number of dice to match the criteria, and counting those dice and comparing them against the number required to successfully complete the task. For now, I’m leaving out those games where the number necessary is one—those fall under the next version.

One of dice pool

Under this system I include all those systems where you need to roll multiple dice, but only use one of them. Some of these could alternatively be considered under the counting dice pool system, but you only need one success. Some RPG systems that generally fall under another system have subsystems that fall under this mechanic: fifth-edition D&D has the advantage (roll 2d20, take the highest) and disadvantage (roll 2d20, take the lowest) mechanic to handle different situations the character faces.

Games like Blades in the Dark, Lasers and Feelings, and the Free League Year Zero games (Mutant Year Zero and Vaesen, for example), use this. Some are more like counting dice pools, and some are more like flat roll over, but the addition of the best of dice pool mechanic increases the odds of success. Calculating those odds are usually not too difficult.

Another game that falls under this is Savage Worlds, although that’s inherently more complex. There your character stats affect the type of die you use (d4, d6, d8, d10, and d12), but you also always roll a Wildcard die (a d6). This makes it more of a best of system, though it’s generally a flat roll-over, where you’re always trying to get a 4 or higher, but mechanics such as exploding dice, modifiers on the die results (-4, -2, +2, etc.), and multiple dice for certain actions, can certainly add to the complexity.  

Finally, some systems don’t use the best die. For example, the Sentinel superhero RPG has you roll 3 dice, whose types depend on the character stats and the situation, and take the middle roll. As it’s a superhero game, different powers can have you using the highest or lowest rolls to have different effects.

Compound systems

Finally, some systems use a combination of these mechanics for basic task resolution. Both the Warhammer: Age of Sigmar Soulbound RPG and the Modiphius 2d20 RPGs (Conan, Star Trek, etc.) combine a counting dice pool with a flat roll-over/under mechanic. In Soulbound, your stats determine the number of dice you roll, but different tasks can have different target numbers for each successful dice and a different number of successes required. Meanwhile, 2d20 has a roll-under mechanic, where your stats set the target number for each successful roll on a d20, and the situation can determine how many successes you need, and how many dice you can roll.

These systems tend to be very flexible, but also very complex to figure out odds. Where it’s spelled out in the rules (for Soulbound, situations such as spellcasting and combat have clearly set target numbers and success count effects), you can hope that the developers have figured out how to best balance the system. But on the fly calculations are much more difficult, and hopefully the developers have at least provided a table to make it easy for the gamemaster to figure out.

Conclusion

So I bring up all these systems to give you an idea of what’s available, both in case you’re looking for a system to play, and you’re considering developing a system. I’ve thought about it a bit, and here are my thoughts on what should go into developing a system:

·       Consider how often you want the characters to succeed rather than fail. D&D is balanced around the idea that for an easy task (DC 10), even the least qualified player character should succeed about half the time, while the most qualified character succeeds about 80% of the time. As you level up, the most qualified character succeeds more often, and can take on more difficult tasks with a reasonable chance of success (a tenth level character with proficiency and a maxed out attribute would succeed at DC 20 50% of the time), while the least qualified character doesn’t improve. For this reason, specialization is important in D&D, and most parties have at least one specialist for each common situation. In combat, the odds seem to be built around a 65% chance to hit with an attack.

·       Consider how often extraordinary successes or failures happen. Do you have critical successes and failures? How often do you want them to happen? Some games use exploding dice (Savage Worlds, Against the Darkmaster), where if you roll high enough or low enough, you roll again and add it (or subtract it!) from the total, and consider an extraordinary success to be a particularly high roll, something that usually only happens when the dice explode. Other games have special rules for adjudicating certain rolls on the dice (D&D’s critical successes and failures on a 20 and a 1, and the One Ring’s Gandalf and Eye of Sauron die faces). With a summing dice pool, really low and high rolls become less common, so you may have to set the odds carefully to get these extraordinary successes and failures regularly.

·       Consider what’s easy for both the Gamemaster and players to adjudicate on the fly. PCs don’t need to know the exact odds, but they should have a general idea of what their characters are good at, and when the odds are for or against them. Gamemasters often need to set the difficulty, and for that, they should have a good idea of what the odds of success or failure are for their characters.

2d10 Combat

Many RPGs center around combat, so it's important to get it right. So I think my combat is going to blend ideas from Pathfinder 2e, D&D 5e, and Warhammer: Age of Sigmar Soulbound.

Actions

The main idea I'm borrowing from Pathfinder is the idea of actions. Every player gets three actions. Everything they can do uses those actions. Some things--movement, attacks, a few non-attack spells--take one action. Other things, like loading a crossbow, or casting most spells, can take two or three actions. Some things--for  example, certain powerful spells--could take up to 6 actions, and have to be split between turns.

In addition, players get a reaction each round. The reaction works for opportunity attacks, and other things that only take a single action. This way you can ready an action--spend an action on your turn to set the conditions to trigger an action.

Pathfinder 2e uses penalties to make it difficult to make multiple attacks on your turn. You can use two actions to make two attacks, but the second attack has a -5 penalty. If you use a third action to make a third attack, you take a -10 penalty. I don't really care for this, and would probably use something like D&D 5e's Extra Attack feature. You can only make one attack during your turn unless you have an ability that lets you make an extra attack. And that includes spell attacks.

Damage by Degree

When you hit with your weapon, the damage will be a base amount (based on 0-5 for your weapon + Fortitude) times the number of degrees of success. The calibration will generally be that rolling a natural 10 will score 1 degree of success, possibly 2 against brutes--high hit points, low defense monsters. Getting an extra +1 degree of success is relatively easy (you'll get a >=15 or a Double 6 or Double 7 23% of the time), but while you could get +2 or even +3 on the roll, that will be extraordinarily rare (you'll roll a Double 8 or Double 9 only 2% of the time, and a Double 10 only 1% of the time). So most monsters will have HP balanced around how many hits they can take with 2 degrees of success from the PCs. At first level, the base damage will depend on the character, but a Warrior with a huge, two handed weapon should do about 10 base damage. So most hits will be 10-20 points of damage, and only if he's very lucky (1% chance) will he do 40 points of damage. I think at first level that 1% chance should probably take the enemy down.

At 20th level, most of the players shouldn't be getting more degrees of success fighting enemies of the equivalent level, but an optimized Warrior with a +3 magic weapon (which applies to both damage and attack bonus) may get one extra degree of success. So on average, the warrior will be doing 2-3 degrees of success. However, I expect that he will be doing considerably more base damage. Assuming magic weapon, a 20th level Warrior with maximum Fortitude and a weapon with a base value of 5, his base damage would be 20. He would also get two attacks most rounds (maybe three, but that's harder to achieve if you need to move between targets). So now he's doing 40-60 per attack, and attacking twice. I haven't taken into account how often he'll miss, but I imagine he'll be hitting most of the time.

Instead of a Warrior, let's consider the Expert. They don't do as much base damage. They do, however, have an ability that increases the degrees of success when they hit with a weapon. They'll probably tend to use weapons that allow them to add Agility to damage, which either have a long reload time (crossbow), or do low damage. So their base damage at level 1 is likely to be 6 at most, and at level 20 is unlikely to exceed 12 (even using a +3 weapon). They do, however, have an ability, Precise Strike, that, if their attack hits (scores at least 1 degree of success), they can increase the degrees of success. This means that at level 1, they should be doing 2-3 levels of success, potentially 12-18 damage. At level 20, they'll probably be doing 6-7 degrees of success on a hit. That's 72-84 damage. But they'll only get one attack per round.

Spellcasters rely on their spells, which should scale in a reasonable way, but I imagine they may apply conditions or spread damage around more often than they'll compete on single-target damage with the warriors.

Hybrid characters will get lesser versions of these features, possibly coming online at later levels and not scaling as quickly (only going as high as +3 damage or +3 degrees of success). They can be combined with each other, or with spells. For example, I intend to give the Holy Knight a 0th-level spell that allows his attacks to do 1 degree higher success against outsiders or undead, 2 degrees at 11th-level (and probably ignore 1 or 2 degrees of resistance as well).

Zones

One thing that I like is using theater of the mind for combat, something that is easier to do in some systems than others. I'd like to make my system friendly toward that, without requiring it. That brings me to the idea of zones, which is the way combat maps are handled in Soulbound. I'll refer to combat using zones as zone combat, and combat using miniatures on a grid as grid combat. 

A zone is an area of combat, defined as much by the terrain as size. A smallish room (up to 30'x30') is a zone, so is the hallway, and also the other small room, while the large audience chamber might be two or three zones. A bridge over a river might have three zones, one side of the river, the bridge itself, and the other side of the river. The river itself could be another zone.

Zones affect range and movement and area of effect, but it's not hard to keep it pretty simple. It takes one action to move from one zone to another. It takes another action to move close enough to engage someone in the same zone as you in combat. Engagement is another word for being close enough to an enemy to attack them with a melee weapon, or for them to attack you. If you're using miniatures, you can just see which miniatures are adjacent, and not need to keep track of engagement specifically.

In zone combat, engagement is an important method to keep track of who you can attack with a melee weapon. Either combatant can initiate engagement, and if multiple enemies engage with you, you can be engaged with multiple enemies. If, however, you are engaged with one enemy and you want to engage with another one, you'll lose engagement with the first enemy. If you are engaged, you take an opportunity attack when moving to another zone or moving to engage with an enemy unless you use a step action to disengage. Engagement is not transitive--if you engage an enemy, and an ally engages them too, and another enemy engages your ally, you aren't engaged in combat with the new enemy. Your ally is engaged with both, but you'll need to engage with the new enemy to attack them, and doing so means you'll no longer be engaged with your current enemy--you'll either need to disengage or take an opportunity attack. 

If you have a weapon with reach you can attack someone in the same zone without engaging. All other melee weapons require you to be engaged. With a ranged weapon with short range, you can attack anyone in the same zone or an adjacent zone, with medium range, you can attack anyone two zones over, and with long range, you can attack anyone on the battlefield assuming you have line of sight.

Usually, area of effect spells affect an entire zone. Some large area of effect spells could affect two adjacent zones or the entire battlefield, though area of effect could come into play.

The air generally counts as its own zone, so someone with flight can easily attack any zone (assuming the zone doesn't have a roof), but he can also be attacked by anyone with a short ranged weapon.

Now I do want rules that also work for miniatures and squares, so I'd want to present both. I don't think you need the engagement rule if you are using miniatures--you engage by moving adjacent to them, and you disengage by taking a step (moving one square with the miniature), if you don't want to take an opportunity attack. The engage action is really just a move action within your zone--you move to get close enough to attack an enemy who's in the same room.

I may also need an action to allow someone to block the way between two zones, assuming the GM agrees the passage is narrow enough. I think in that case, an enemy can't get past him unless they make a roll (probably a Fortitude contest of some kind), but the defender can't take the engage action. Enemies in both zones can engage with him, though. I probably need to make this an action that would work for both zone combat and miniature combat, so I'll need to think of how the rules would apply.

I think I want two levels of difficult terrain, difficult and very difficult (maybe think up a better name later). Difficult terrain halves your movement, and very difficult terrain cuts it to a third. (Remember the Elf feature that ignored a level of difficult terrain? This is where it applies.) Using zones with difficult terrain, I can say that if a zone is difficult terrain, it takes two actions to move, either to engage with someone or to move to a new zone, or three if it is very difficult terrain. Moving from one zone to another takes a number of actions equivalent to the highest difficulty of terrain of the two. If one zone is normal and the other is very difficult, it takes three actions to move to the very difficult terrain or away from it.

Spellcasting

I haven't decided yet whether casting a spell grants an opportunity attack. I'm leaning towards no. However,  I do want to allow an enemy to interrupt a spell. If they ready an action to attack you when you cast a spell, they can force you to make a concentration check to keep the spell. By the same token, if you cast a spell that takes more than one round, then if you are attacked between starting the spell and finishing it, you also need to make a concentration check or lose the spell.

Making a ranged attack may grant an opportunity attack, however, including a ranged spell attack. Perhaps both would require a concentration check to still attack, otherwise you lose the spell or the ammunition as the magic or arrow goes wide.

Finally, I'd like to borrow from Pathfinder 2e's way of sustaining spells. You don't cast one spell and concentrate on it. Instead, you need to use one of your actions to sustain a spell. You can sustain more than one spell, but you quickly run out of actions that way. Pathfinder 2e doesn't let you end concentration on a spell by just doing damage to the caster--there are no concentration checks for that. Instead, you stop someone's sustained spells by causing a condition that prevents them from using an action to sustain the spell. I do like having to concentrate to maintain a sustained spell when you're hurt, so I may keep that aspect of concentration. Your degrees of failure determine how many sustained spells you lose if you're sustaining more than one spell. I may let the player decide which ones they lose.

Two-Weapon Fighting

Here's another place I borrow from Soulbound. You can attack with two weapons with one action, either attacking the same enemy or two different ones you're engaged with. However, in order to do so, both weapons need to have Agility for both attack and damage (currently, there are only two: daggers and rapiers, but I could see adding unarmed attacks for martial artists, perhaps some paired weapons purely for dual wielding, maybe even bucklers will be treated as an offhand weapon). However, for both attack and damage, you divide your Agility in two and apply half to each, rounding up for your main hand (whichever is holding the larger weapon), and rounding down for your off hand. This is similar to what you do in Soulbound, where you divide the number of dice into dice for one weapon and dice for another. I may add talents for Two Weapon fighting. If you have an Agility of 4 or more, you can take a Talent that will let you add +1 to each weapon's attack and damage, and if you have an Agility of 6 or more, a Talent with the first one as the prerequisite will let you add +2 to each weapon's attack and damage. I may also add +1 to Defense when you are wielding two weapons but only attack with one, but I haven't decided whether that's automatic, or part of these or a different Talent.

Resistances

Another thing I'm mulling over is resistances. Some creatures are just hard to hurt with certain elements. For example, casting a fire spell at a fire elemental should do a lot less damage than against a plant creature. However, I don't like the idea of complete immunity. There should be at least some way to harm enemies with fire spells, even if they're resistant.

My initial idea is to have resistance that builds off the idea of degrees. When you hit a fire resistant monster with fire and achieve any degrees of success, the number of degrees of success is reduced by one. More resistant enemies can have more degrees of resistance. A fire-breathing dragon has two, a fire elemental has three. However, when you have an enemy with three degrees of resistance, that can turn a degree of success into two degrees of failure. If I have fumble rules (something that I'm still considering), then I'm not sure that's fair. However, if I start setting limits: a resistant creature can't reduce the success of the roll below a near miss, for example, then I run into an order of operations problem. 

Let's say I introduce a talent that says when you score a success against an enemy with fire, you deal an extra degree of success, or two degrees of success if they're resistant.

Let's get back to my fire elemental with three degrees of resistance. I score two degrees of success, they apply their resistance to turn that into a near miss, and then I apply my talent--only I can't, because the talent says I can't apply it unless I have a success first. Okay, let's say I solve that issue, and I say that I can apply the resistance first, then the talent--then it goes to two degrees of success again. But if I go the other way, and add my two degrees of success first, bringing it to four, then deducting three degrees of success, I only have one degree of success. By applying the resistance first, I actually did more damage than I would have if I applied the talent first, because I ran into the limit.

I think the easiest way to do this is to not set limits to resistance, and allow it to turn a hit into degrees of failure. It's really no different than attacking someone with a very high defense. Failing to do damage is more a matter of the heavy armor than a fumbled roll. You can just open yourself up if your attacks, no matter how skillful, are ineffective.

This does still leave the problem that I still have some degree effects with conditions. I don't want to change the Precise Strike rules, where I get more degrees of success when I hit, since I don't want to make my roguish characters more likely to hit than anyone else. I think, instead, I'll apply the conditional degree effects only if the condition still holds after the other degree effects. It seems like I can, however, make resistance unconditional, and adjust the elemental damage to something like "Your fire attacks ignore two degrees of fire resistance. In addition, any successful fire attack gains one degree of success."

Recovery

I said this earlier, but I want PCs to recover hit points after every battle. I haven't decided yet whether I want this to be a short rest thing, in that they need to rest for an hour after a battle and recover all their hit points. If so, I may also tie it to recovery of spell points. Alternatively, I may just make it so that if you have five minutes to catch your breath after a battle, you recover all your hit points. (In this case, I'd keep the spell recharge rate by hour and not require rest to do so.) The key to understanding this is that hit points are not health. They measure your endurance, your ability to roll with the punches, and otherwise avoid serious injury. Only when your hit points go down to 0 are you hurt enough to take you out of the fight. And any significant injury is sufficient to take most people out of a fight.

When you recover from being taken down to 0, you return with an penalty. Some games call these Wounds. They can be tied to levels of exhaustion in D&D (especially the One D&D version which has ten levels instead of five). In earlier posts, I called it Fatigue. But I think I'll borrow from other games and call this Stress. Stress can be physical--injury, bruises, sore muscles--or mental--being worn out, discouraged, depressed. The total amount of Stress you can endure is Fortitude (minimum 1) + Will (minimum 1), for a minimum of 2. Most players will want more than this. For each level of stress, you get a -1 to all rolls. Once you exceed your maximum, you are broken. This doesn't necessarily mean you are dead, but it does mean your character is no longer an active participant in the adventure, and cannot make any rolls. You recover one point of Stress per full night of rest, or two points if you rest in a comfortable and safe location (in town, or your team base, or some other safe area).

Going down to 0 is one way you can gain Stress, but not the only way. Traveling in hostile terrain (arctic or desert conditions, for example), 2 degrees of failure on some checks, the price to turn an important Near Miss into a success.

So, if you regain hit points each time you finish combat, that means you need less HP, right? Well, not so fast. In most groups, players are going to be close to full health before most battles. Also, damage can stack up quick if the enemy rolls a dreaded Double 10. So you don't want to make the HP too much lower. Here's what I'm thinking--you start with 10 + Will (minimum 1) + Fortitude (minimum 1), and add a fixed amount per level in each class. This amount can range from 2 through 5, depending on the class. Initially I'm thinking 5 for Warriors, 4 for Skirmishers and Champions, 3 for Experts and Adepts, and 2 for Magi. The HP will start higher, but scale slower. Pretty much everyone will have a decent Fortitude or Will, though both may be rare.

Death

So if you don't die when you go down to 0 hit points, and you don't die from hitting your maximum Stress, can you die in this game? Well, two facts come to mind: One, death usually sucks. Two, fear of death is a great motivating factor.

In general, going down to 0 does not mean you die. But an enemy can use three actions to coup de grace a downed character. If the entire party goes down, then it's understood that the surviving enemies could very well kill them. Not being able to fight back as they put you out of your misery will definitely kill a character. A coup de grace will definitely be part of the rules. It will take three actions, so most enemies won't do it while in the middle of combat, but a GM can use it to put some fear into his players.

The GM can also declare that some actions are so risky that failure may mean death, such as trying to  jump over a gorge. He should inform the players before they attempt to do so, though.

Another way to die is to go down in a Blaze of Glory.  This is a rule I'm borrowing from Soulbound. If you're at or are knocked down to 0 hp, you can declare that you're going down in a Blaze of Glory. You immediately stand up with 1 hp and you take your turn, your spell points are fully recharged, you have three actions, you are immune to all damage and all conditions, all rolls you make are Double 10s and ignore resistance, and all rolls to save against your rampage subtract two degrees of success. At the end of your turn, you immediately die and cannot be brought back (I'm not sure whether there will be resurrection in the game at all). Then play returns to where it left off in the turn order before you took your turn.

Can this be abused? Definitely. It's up to the GM to make sure it's not. For example, the first time it happens, let the player make a new character at the same level. If he does it again, the next character can be a level lower, and then another level lower. Even going out in a Blaze of Glory doesn't make a 1st level PC stand out among a group of 7th level PCs.

Conclusion

At this point, I think I'm done with this series of posts. I've described the system and how it works, thought through some numbers, and done about as much as I can do without playtesting. In some ways, coming up with the basic rules are easy. The hard part is in the details: working out the features and progression of each class, coming up with all the spells and spell schools, creating monsters, writing it all out in a book, and playtesting it all while tweaking the numbers. Overall, it's a lot of work, and I'm not likely to do it unless I have a group that's interested in playing this game. We'll see.

2d10 Equipment

I could spend a lot of time on equipment, but I intend to keep this simple. Besides, the only equipment most people are interested in is weapons and armor, so I'll focus on that. 

Each weapon has an ability score used for attack, an ability score used for damage, and a constant added to damage. This constant is between 0 and 5, most commonly 3 for most one-handed martial weapons. Most weapons use Agility for attack rolls, and Fortitude for damage rolls, but there are exceptions.

The first exceptions are the crossbows, daggers, and rapiers, which all use Agility for both attack and damage. Each of them has a disadvantage. Daggers have a 0 damage bonus. Rapiers are slightly better at 2 but are special weapons requiring particular training.  And crossbows take significant time to load.

The other exception are heavy, two-handed weapons. These use Fortitude for both attack and damage. There are a few special one handed weapons, such as Dwarven waraxes, that have this feature as well. Normal swords need Agility for attack and Fortitude for damage.

Armor will work closer to a cross between 5e and 3.5e. They'll be divided between light, medium, and heavy, though unlike 5e, you don't need training in light to get training in medium, though you will need training in light or medium to get training in heavy. Like 5e, the armor class will be calculated using a base value plus Dex (or in this case, the higher of Agility or Mind). However, the maximum Agility or Mind bonus allowed will depend on the specific armor, rather than just being dependent on the light, medium, or heavy type. I'll probably also bring back an armor penalty based on the specific armor, though it will not grow to the ridiculous heights it could in 3.5e and Pathfinder.

One thing I want to do more with is Crafting. I want rules to craft not just ordinary armor, but magical armor. This will take two forms: casting enchantments on ordinary armor, or crafting (or improving) armor with rare materials. Those materials can be quest rewards or discovered while adventuring, but they usually can't be purchased. Whether using raw materials or casting spells, there will also be an estimated cost in gold, which will probably be about a quarter of the purchase price of the item (most items cannot be purchased, but there is an attached price for reference). That amount represents costly materials and components needed to craft the item.

Crafting an item is a long-term task. To complete an item will require a number of success tokens proportional to the difficulty of creating the item. Each day, the player spends an amount equal to the total cost divided by the number of necessary success tokens, and rolls a Crafting skill check. Each degree of success adds a success token, while each degree of failure subtracts a success token. The item is complete once the number of success tokens equals or exceeds the number needed to complete the item. Notice that very good rolls could result in the project costing less than the estimated cost.

Casting a spell on the item is a ritual, that usually takes multiple hours since the spell point cost of making an enchantment permanent is greater than a magus's total spell points. Remaining focused on the spell during the course of the ritual generally requires multiple rolls.

Crafting tends to take days, rather than hours, but it has the potential to cost less, and a failure on one roll doesn't necessarily ruin the project. Moreover, projects may be put aside and returned to later. Casting a spell takes hours, but one failed roll means the whole spell is lost, along with any material components.

The ABCs of Character Origins

Gruff underground dwarves, woodland elves, pastoral hobbits--we all know the stereotypes. Recent versions of roleplaying games have tried to lean into them a little less fully. Allowing them, sure, but also allowing characters to play against type, and build the characters they want.

To that end, the newest version of D&D tied all the ability bonuses to backgrounds, which generally reflect the career you had before adventuring, while making the racial options (now called species) more focused on biological traits rather than cultural ones. For example, by giving dwarves tremorsense, but no longer the usual weapon training. While I appreciate making things more open, I feel like this goes a little too far.  For one, neither background nor species reflect the culture of the character, and I'd like that to have a role.

So rather than just selecting species and background, I think you should build your characters with ancestry, background, and culture.

Ancestry

Ancestry is the term used by Pathfinder 2e, but I think I prefer the word Kind, partly because it fits well--dwarvenkind, elvenkind, and humankind. I don't like species, because it overlooks a key aspect in many fantasy realms: they can interbreed.

I like giving each Kind an ability bonus (with options), a couple of traits, and a decent list of talents (feats) which are specific to them. Here's my first draft for the four main ones: humans, dwarves, elves, and halflings.

Dwarf

Ability: +1 to Fortitude or Will

Traits: Low-light vision and blindsight (10'), Dwarven Toughness (increase levels of fatigue and ignore the penalty for the first two or three levels)

Dwarven Talents: Resistance to Poison, Hard to Knockdown

Elf

Ability: +1 to Agility or Mind

Traits: Low-light vision, Ignore 1 level of difficult terrain

Elven Talents: Ranged attacks bonus, Elven magic

Human

Ability: +1 to any

Traits: Extra talent and skill and specialization

Human Talents: Quick learner (additional skills + languages), Dabbler (learn a magic school even if you don't meet pre-requisites)

Halfling

Ability: +1 to Agility or Will

Traits: Small, Lucky (roll a Fortune die when roll low double)

Halfling Talents: Hard to See, Courageous

I want to get rid of darkvision as it exists in D&D 5e. For one, everyone has it, and two, the way it works based on range from a character doesn't make much sense. Instead, I'd give low light vision, where dim light is treated as bright light, and treat light according to the distance from the source, not from the one seeing it. For complete levels of darkness, I would give dwarves not darkvision, but blindsight. That can have a limited range, as it's specifically understood to not be sight, but to act like sight. Since no one has a way to see through complete darkness, we don't have to worry about magical darkness working against darkvision.

One of things I'd like to do is take some of the features which are iconic traits in other games and make them talents, which are like feats in that you can take them at certain levels. But I won't make players choose between talents and raising their ability scores.

For people who are of mixed-kinds (half-elves, et cetera), I'll let them choose the ability of one kind and one trait from the other (possibly two, if each Kind has at least three traits). But they would have access to all of the talents of both Kinds, as well as a special talent that lets them pick a trait from either parent Kind.

Culture

Culture is how someone is raised. It can be connected to their kind, but it doesn't have to be. I'd expect to have cultures such as Dwarf Hold, Elven Forest, Human Town, and Halfling Settlement. But I'd also have other ones, such as City (with the understanding that cities are mostly cosmopolitan, and many Kind settle there), Rural, Wilderness, Seafaring, and Plains. The culture would grant a language, weapon training (often in martial or specialized weapons), perhaps armor training, and +1 to an ability depending on the culture (usually granting a choice between two possible abilities). There would also be a skill and a specialization based on the culture.

Background

Background is an important part of a character's past. It basically represents their career prior to adventuring. They may have been a smith or a miner or a guard or a wizard's apprentice or an acolyte. The background grants +1 to one of two abilities, a skill and specialization related to their background (Labor, Craft, and Profession for a lot of them, but perhaps some of them offer more adventuring skills), and some basic equipment associated with the profession.

Summary

When building a character, players select a Kind, a Background, and a Culture. This grants them three ability points, which they can put all in different abilities, the same ability, or spread out, as long as no ability exceeds 4 at least one. Their Culture and their Background should each grant them a skill and a specialization, their culture grants them a language and weapon training, and their Background grants them some basic equipment. This is before selecting a class.

Expert and Expert hybrid classes (Adept and Skirmisher) get the most skills and specializations. But I think that even Warriors, Magi, and Champions get some skills and specializations.

2d10 Classes

Classes are an important part of Dungeons and Dragons. There are four basic classes, which have been around a while: cleric, magic-user, thief, and fighting man. Nowadays, we call them cleric, wizard, rogue, and fighter. But part of what makes recent editions of D&D fun are the wide variety of classes (12 from the PHB + 1 from Tasha's), and the subclasses, of which there are over 100 official ones, and thousands homebrewed ones.

Classes and subclasses are the main way that players try to capture the archetype they want to play. Building the character you want involves selecting the right base classes and subclasses, and often times multiclassing to get two or more classes, and sometimes additional subclasses.

There are a number of games that try to do away with classes altogether. GURPS and Mutants and Masterminds, for example, rely on point systems that allow you to build, in theory, any character you want. The problem is that point systems tend to be really complicated, and building a character that way can take an excruciatingly long time. There's software to help, and you'll probably need it.

I think for my 2d10 non-OGL game, I want to keep the idea of classes and subclasses, but simplify things a little. Many games boil down the game to three classes: Warriors, who do the fighting, Experts, who have a lot of capability with various skills, and Mages, who cast magic. That is, in fact, what D&D does for sidekicks--NPC party members who have a stripped down character classes. In this approach, Warriors stand in for Fighters, Experts replace Rogues, and Mages replace both Clerics and Wizards, depending on which spells they have. But this isn't the only game that does three basic classes. There's also Fantasy AGE, True20, Worlds Without Number (which also adds Adventurer, which functions as a hybrid of any two of the three main classes), and Cypher, which all divide classes this way, though often with different names.

I think I want to start with the simplified three classes, but also introduce three hybrid classes, and then add 5e's concept of subclasses. In this system, each class in D&D can be represented by a subclass in the 2d10 system.

Three of the classes are the same as used elsewhere: the Warrior, the Expert, and the Magus*. But the other three are hybrid classes: there's a Warrior-Expert hybrid (let's call that a Skirmisher), a Warrior-Magus hybrid (Champion), and an Expert-Magus hybrid (Adept). Each of these helps to fulfill an archetype, and the subclasses make those more explicit. For example, Clerics and Wizards fit under the Magus class, Paladins and Rangers subclasses can fit under Champion (or possibly Adept for Ranger), Bards are an Adept subclass, and Monks are a Skirmisher subclass.

One thing I want to do is allow the hybrid spellcasters not to feel underpowered compared to the Magus, while making the Magus the best spellcaster. To that end, I think that the Champion and Adept will get access to fewer spell schools, but some of them will be unique to their classes (or subclasses), fewer spell points, and have their spell points recharge more slowly. But they'll still be able to cast spells up to the 20th level, and if they invest in Will, will still have more than enough spell points to make it work. The spell point recharging will be part of the class table, so to determine the total amount, you can just add them together. Champion and Adept will recharge their spell points at a rate of one-quarter their level per hour, rounded to the nearest whole number. So at level 1 they won't recharge at all unless resting. Magus will recharge his spell points at one-half his level, rounded up. Finally, the Magus will have a feature that will allow him to meditate to recharge all the spell points he would receive in the next hour in five minutes, but at a cost. Possibly a point of fatigue, but I'm actually thinking that reducing his max spell points by the same amount until he rests might work better.

So here's a rough sketch of classes and subclasses:

• Warrior - This class will get a scaling bonus to damage. It is also one of the simpler classes, needing only Fortitude and Agility.
• Berserker - Like the Barbarian.
• Archer - Basic, non-magic archery
• Soldier - The basic fighter.
• Expert - Aside from getting more skill training and specialization, they also get a precision strike (like sneak attack), that increases the degree of success on attacks in certain situations, but only on a hit. Since damage is a base amount times degrees of success, this can be a significant bonus to damage.
• Thief - I'm considering giving them a feature that lets them "steal" from the party. Basically, if they're in a situation when it would be handy to have something another player has (like a potion or scroll), then can search their pockets, and other players can offer up items. 
• Alchemist - I haven't fully decided how this works, but a non-magical maker of dangerous items could be fun.
• Investigator - I want an Expert that's less Thief and more Investigator, able to find secrets and put together clues. 
• Magus - The primary spellcasters get more spell points, more spell schools, and they recharge spell points quicker. They can also ritually cast spells, which allow them to spend more spell points than they actually have.
• Wizard - They have spell schools that emphasize not just damage but also the manipulation of magic.
• Priest - The priest has spell schools that heal and buff.
• Druid - The nature priest. I think I'd like to add shapeshifting, but I'm not 100% sure that I want to make that specific to the druid. They have unique nature spell schools, plus a mix of healing and damage, but not the buffing or magic manipulation.
• Skirmisher (Warrior-Expert) - As a cross between Warrior and Expert they get some of both. The scaling to both damage and precision strike is slower, and they get fewer skills and specializations than Experts but more than Warriors.
• Scout - Their job is to sneak in and observe. Is a ranged attack specialist, with high stealth.
• Swashbuckler - Like the rogue subclass, they get proficiency in rapiers and bucklers, and are particularly good at Acrobatics (Stunts)
• Martial Artist - The basic monk, but with less emphasis on the mystic, more emphasis on cool moves and traversal.
• Champion (Warrior-Magus) - This is a cross between Warrior and Magus. One of their key features will be Empowered Strike, which allows them to use Will instead of Fortitude for damage with weapons. While they get fewer spell schools and spell points than Magus and their spell points recharge slower, they will also get some unique spell schools based on their subclass.
• Arcane Archer - Their spell schools empower their arrows.
• Holy Knight - The paladin. Their spell school(s) is particularly effective against undead and outsiders, though not useless otherwise.
• Witch Knight - The gish.
• Adept (Expert-Magus) - This is a cross between Expert and Magus. They will get Precision Strike but it scales more slowly than Expert, more skills and specializations than normal (maybe even as many experts, but I haven't decided yet), and spellcasting, which will be about equivalent to the Magus
• Bard - Like the D&D class. They get at least one unique spell school of magical songs.
• Shadow - Basically like the Way of Shadow Monk, Shadowdancer, Ninja, or Assassin. Their unique spell school(s) emphasizes shadows and stealth. 
• Ranger - Like the D&D class, their emphasis is on nature, with access to spell schools that support that. They will be primarily ranged attackers.

In order for this to work, the subclasses will need to kick in at 1st level, so that features that define the subclass (like unarmed fighting for the Martial Artist) can be added at first level. Otherwise it'll be similar to subclasses in D&D 5e, with features that come in at regular intervals. Maybe not the same intervals as 5e: perhaps first, third, seventh, tenth, fourteenth, and seventeenth.

As well as these hybrid classes, I also intend to allow multiclassing. One of the fun things about D&D 5e is the ability to multiclass and get interesting features. The trick, though, is to make sure there's a price for doing that that's significant enough that people wouldn't be tempted unless they have a specific idea.

* I chose the term Magus partly because I like the word, and partly because it gets to the origins of the term magic. The Magi (it's the same term used in the Bible for the visitors of Jesus, but not necessarily the same people) were originally a priestly caste/clan in ancient Babylon and Persia. Their rituals were exoticized by the Greeks and became the origin of the idea of magic. It also speaks to the fact that in the ancient world, there wasn't really a distinction between magic and religion. Rituals that appealed to the gods and/or spirits to do what you wanted was religion when you did it and magic when foreigners did it.

2d10 Magic System

 In this post, I'm exploring magic systems in RPG, and what I want to borrow for my 2d10 system.

Dungeons and Dragons 5e uses a variant on its Vancian magic system. In older editions, magic-users would have a number of spell slots at different levels (the spell levels you had access to weren't the same as your class or character levels). Magic-users would fill those slots with the spells they wanted to cast that day (this was called memorizing the spell). Then once they cast their spell, they couldn't do it again as that slot was now empty. The only way to cast a spell twice was to put the same spell in two slots (memorizing it twice).

Fifth edition still uses the term slots, but it works differently. The term slot is now outdated, though it's still the term used. The spells you have prepared don't match the slots, you don't lose the spell once you cast it. Instead you spend a spell slot to cast a spell, and can choose which spell you're spending the spell on only when you cast it. If you want, you can use all your slots to cast a spell again and again, assuming that the level of the spell is equal to or less than the level of the slot.

But D&D does have an alternative magic system, explained in the Dungeon Master's Guide, called spell points. When you want to cast a spell, each spell has a cost based on the spell level, and the number of spell points you have depends on your spell slots.

What I'm proposing is something similar to that, but based instead on the spellcasting in MERP, Rolemaster, and Against the Darkmaster (VsD). In those games, instead of learning individual spells, you learn a set of spells (called a Spell Lore in VsD). As you increase in levels, you can cast the higher level spells in the Spell Lore. So all fire spells are in the Eldritch Fire Spell Lore, and as you level up you gain spells  from a fire touch attack to a bolt of flame to a ball of fire. The cost of the spell in Magic Points is equal to the spell's level, which is equal to your character level.  The number of Magic Points you have depends on the class and your magic ability score and is multiplied by your level. 

However, I think that I want to let the Magic Points recharge more quickly than VSD does. So that the caster can regain a portion of their spell points every hour (similar to the Aetaltis campaign world). In that case, we'll need to keep the scaling on spell points slower, and make spells more expensive.

VsD has ten levels, and a spell for every level. D&D grants new spells every other level, but calls the spells wizards gets at level 1 first level spells, the ones they get at level 3 second level spells, and the ones they get at level 5 third level spells. This is definitely confusing. I think I'd like to clear that up with my system.

So let's call the spell lists Spell Schools (as that's how D&D groups them). Every spellcaster gets a number of Spell Schools (exact number to be decided when we get to classes). There are, for example, the Fire School, the Water School, Enchantment School, Song School (for the bards, of course). Each of the schools have spells at different levels, but not necessarily every level. In fact, I'd like the distance between the spells to increase as levels go up.  My initial thought is 0, 1, 2, 4, 6, 9, 12, 16, 20. That's nine levels of spells, and you don't get the highest level until level 20. The number of spell points each spell costs should be equal to the level. So a level 0 spell costs nothing, and you can cast it as many times as you want. Level 1 spells cost 1 spell point, level 5 spells cost 5 spell points, and level 20 spells cost 20 spell points. One thing I like is that you don't need to have spells at the same levels for every School. You can, instead, have spells at different levels, and more spells in certain schools.

That indicates that high level spellcasters should have at least 20 spell points if I want them to be able to cast any 20th level spells. With that in mind, I can figure out how to calculate spell points. My plan is to make it Will plus a class constant (which ranges from 0 to 5), times the base modifier. The base modifier is the same scaling as skills, which is equal to the character level divided by four rounded up. So 1 for levels 1-4, 2 for levels 5-8, 3 for levels 9-12, 4 for levels 13-16, and 5 for levels 17-20.

The maximum any ability can be at level 1 is 4, and let's say mages get 5 spell points, so at level 1 they have 9 spell points. However, that doesn't increase until level 4, where, if they put 1 point in Will, they now have 10 spell points. At level 5, however, the base modifier increases by 1, and they have 20 spell points, just in time to cast level 5 spells for 5 spell points, meaning they can cast 4 before they run out.

The maximum number of spell points they can reach is 60. Which is a lot of first level spells, but only three level 20 spells.

But as I discussed earlier, I would like them to recharge spell points every hour. I'm not sure how fast that should happen. I could see making it as slow as the base modifier, or making it Will + class constant, or even making it the caster level (that might work best with multiclassing, if some classes add 0 or half to the recharge number). Right now I'm thinking half the level for pure casters, and a quarter the level for quarter casters.

D&D has a concept called upcasting, and VsD has a similar concept called spell warping, where you can increase the effect of the spell if you cast it at a higher level. There was a more flexible version of this called metamagic in D&D 3.5 and Pathfinder. I'd like to borrow this, but rather than a higher level, I'd like to add a multiplier on the spell point cost. This means that you don't need to be higher level to make a spell more powerful, but you can burn through your spell points quickly if you enhance the spell too much.

But you can also cast spells that are upcast to use more spell points than you have. This will be the basis of ritual casting. You can either share the burden with another caster who knows the spell, or you can cast slowly enough that you recharge the spell points as you cast. That takes hours, maybe a whole day, and you may have to roll Concentration to see if you can maintain the casting that long.

Finally, there's a question of which ability to use for the casting stat--whether it's a roll to cast, or a DC the target needs to save against. Usually this is the base modifier plus an ability score. It should probably be either Mind or Will. After some consideration, I think that spells which have a physical effect should use Mind, and those that have a mental effect should use Will. This likely means different stats depending on the spell school. It could also be that attack rolls should use Mind while saving throws use Will. I believe that saving throws will be 10+Will+base modifier.

Revisiting 2d10, doubles, extra dice, and degrees of success

In my first post on this topic, I talked about 2d10 as a variant for Dungeons and Dragons, and focused on the ways it interacted with its existing systems. Because of that, I limited how far I used things such as degrees of success. Now that I'm considering, because of the OGL mess, how I would build a system around 2d10, I'm rethinking how I did things in that post, and the subsequent Weal and Woe pools.

Math First

First, let's take a step back and consider how much effect do you get from rolling an extra die (3d10), and then selecting the best or worst two. Let's revisit this table from my Abilities and Skills post:

Odds of rolling different targets with 2d10 at different levels of ability.

As you can see, even with no training a character would usually pass a test with a target number of 10, a character with either a maximum ability modifier or skill training and specialization (which will give a similar result as those with decent Skill Training and a decent ability score) have a good chance of succeeding on a Medium test, and those with all three have a good chance of meeting a target number of 20 at low levels (but those with only one or two of Skill Training, Specialization, or maximum ability modifier become more likely to reach it at higher levels).

Target numbers of 25 or above are basically there to give those who have mastered a skill something more challenging at higher levels. A target of 30 is almost impossible--it should only be attempted at high levels, and adventures shouldn't hinge on successfully making that check. In some ways, 25 and 30 are more useful to show the odds of the most capable character getting one or two extra successes versus DC 20.

So that's what it looks like if you're only rolling two dice. What if you're rolling three and taking the two best. Then, your odds of success look something like this:

Odds of rolling different targets with 3d10 keeping the two best at different levels of ability.

This makes the higher targets of 25 or 30 look more achievable, as low odds basically double (high odds only change incrementally).

What if you're stuck with the two worst?  That looks something like this:

Odds of rolling different targets with 3d10 keeping the two worst at different levels of ability.

Now really high rolls look practically impossible. Most of the odds that were less than 50% before are effectively cut in half. This suggests that target numbers of 25 and even 30 at high levels are something you should only throw at your players when they attempt something ill-considered and you expect them to fail--but you want to give them a chance to do something epic if they succeed.

Weal and Woe, Mostly Woe

So we want the probability shifting that comes from throwing an extra die, but we probably want to call it something different from Weal and Woe, which is what I was using earlier. I suggest that when a player rolls an extra die, you call it a Fortune die, and when the GM rolls the extra die, you call it a Doom die. This applies no matter what circumstance grants it (spells, favorable or unfavorable circumstances, aid from another party member). The reason for this is that I want to keep my Weal and Woe Fortune and Doom Pools as an optional element, and if we have a mechanic called Fortune dice, we can easily add the idea of a Fortune Pool, as the resource from which those Fortune dice come.

We can also give each player character a fortune point, similar to D&D's inspiration. They can gain a Fortune Point whenever they roll doubles, and spend them to roll a Fortune die. Note that unlike the Advantage/Disadvantage, spending a die for Fortune has no effect on whether the DM rolls a Doom die. You merely have to declare you're doing so before the DM discards a die, and then you each roll, and remove a die in the order you roll.

Degrees and Doubles

In my first post introducing the 2d10 mechanic to D&D, I included two mechanics that interacted with one another, doubles and degrees of success. I stipulated that degrees of success only applied to ability checks, while doubles applied to all rolls that would use a d20 in D&D (including attacks and saves), and had to explain how to handle doubles in each situation.

That said, if I'm creating my own system more or less from scratch, I don't have to adapt it to how D&D handles different types of d20 rolls. That allows me to smooth things out more and make it more consistent. So let's adjust things this way: all rolls have degrees of success and failure. This includes attack rolls, saving throws, and ability checks (though since they're all the same, we no longer need to divide them up this way).

So an attack roll can have one, two, three, or more degrees of success, while a saving throw can have one, two, or three degrees of failure.

That also lets us approach high doubles and low doubles differently. A high double increases your degree of success by one, while a low double decreases your degree of success by one. However, universally, degrees of success and failure are every 5 points above or below the target number. Therefore, it may be easier to treat a high double as adding five to your roll, and a low double of subtracting five from your roll. This results in moving you up and down the success ladder the same, and may be easier to remember. (And it's definitely useful for doing opposed rolls, where a double could change who wins.)

We can also use the skill descriptions to describe what various degrees of success mean for different skills, and spell descriptions for what degrees of failure mean for saving throws (it might be useful to take a look at Mutants & Masterminds, which does this already for a lot of its abilities, with certain conditions being stronger versions of other conditions, so that when you fail against an attack that applies a condition, the degree of failure determines which condition applies).

One thing to think about more in-depth is the concept of zero degrees of success, or a Near Miss. In many contexts, this is simply a failure with no additional consequences. You failed to pick the lock, you missed the enemy, etc. But I'd like to encourage GM's to allow it to be a success with consequences, or at a price. This is especially the case for high, almost impossible to achieve target numbers (anything higher than 20 for most parties). If it's very hard for your PCs to reach the target number, there's still a decent chance of almost making it. In that case, it may be worthwhile to let them have it, but at a price.

So here are some ways GMs can use a Near Miss:

• A failure with no additional consequence. You don't convince the king, but you don't offend him either. You don't find the evidence you were looking for, but you can keep looking. You miss the enemy, but assuming he doesn't kill you in the meantime, you can try again next round.
• A partial success. You try to grab the gold, but only get a few coins. You try to catch the falling potions, but only rescue one. In these cases you did part of what you were trying to do, but not all.
• A success, but it takes ten times as long. This is particularly useful in a situation where the character can simply try again. It's less interesting to have the player roll multiple attempts than it is for the GM to just declare that they succeed, but it takes a while. Especially when the GM uses this to increase tension. What would have taken a round on a success instead takes a minute. What would have taken a minute takes ten minutes. What would have taken an hour takes all day. GMs should always present it as a choice: "After a minute of poking at the lock, it's clear this is going to take a while. Are you going to keep at it, knowing that a patrol may come by at any minute?" Then the GM uses a random roll to determine whether the patrol arrives, using their favorite method to determine if a random encounter happens.
• A success with a consequence. You succeed, but something bad happens as well. You get the lock open, but made enough noise to attract a guard in the meantime. You convinced the king that there's a problem, but his solution is not one you like. You avoid the pit trap, but now your party is separated by it with no way to reconnect. In general, you don't want the consequence to be worse than what would have happened with a degree of failure. GMs don't usually need to give the players a choice to use this option.
• A success at a price. You succeed, if you're willing to pay the price. That price may be gold to pay the guard, or a level of Stress, or a valuable item falling from your pack to the jagged rocks below the cliff you're climbing. In this case, the GM should present this as a choice.

Stress

Many games have different pools for different types of injury. Consider for example the Warhammer Age of Sigmar RPG Soulbound. This has Toughness (an HP pool which you recover after every battle), and Wounds (more significant injuries that take time to recover from). D&D doesn't exactly do this, but the exhaustion mechanic (and especially the one introduced in One D&D) gives us an ability to give players conditions that affect their performance and that take time to recover from. Many tables use the exhaustion mechanic to introduce penalties when players lose all their HP and go down and need to be healed to get back on their feet. With the 5e version, that is very punishing.

But I do think I want something along these lines. Let's call it Stress for now. You receive a level of Stress whenever you go down to 0 HP in combat. It can also be the price you pay to turn a Near Miss to a success, or if you fail an important roll (say you're traveling in a hostile environment and fail your Survival check), or it could represent an injury you receive from a trap. For each level of Stress, you subtract 1 from all your rolls, and when you exceed the maximum, you're down for good. This can mean dead, or just collapsed, unable to get up again.

In One D&D the maximum number of exhaustion levels one can reach is equal to 10; after that you die. I think I'd make that something dependent on the character stats. For example, you can make the maximum equal to the character's Fortitude + Will ability modifiers, but you would need a minimum value for players who decide to dump both Fortitude and Will. I would say if you have 0 in an ability score, you can use 1 instead. (So if you have Fortitude of 3 and Will of 0, you'd have 4 Stress Levels.)

Recharging

D&D 4th edition had at-will, encounter, and daily abilities, and encounter abilities would recharge after each battle. As a whole, people didn't like it. But recently, I've played a number of video games with a similar mechanic, such as Chained Echoes and Pillars of Eternity 2. I like how you can go from battle to battle, and only worry about retreating when you gain wounds which you don't recover from quickly. From tabletop games, I'm inspired by the Soulbound Toughness and Wound mechanics mentioned above, and by the spell point mechanic used in Aetaltis, a D&D 5e campaign. In Aetaltis, spell points recharge, and you regain a number of them every hour.

A Stress, wounds, or whatever I decide to call it gives me a more durable mechanic for injury, that comes with a built-in penalty to rolls. So on top of that, I can have a hit point pool that recharges rapidly after a battle. For spell points, I can have those recharge at a rate dependent on Will and class every hour. This will require a smaller maximum number of spell points compared to spell slots. In general, it'll probably be more spells at low levels, and fewer at high levels, with spell points allowing a few high level spells to be cast or a number of low level spells.

I'll talk about my ideas for magic in a later post.

Abilities and Skills

Here, I'm considering how best to design a non-OGL role-playing game. See my other 2d10 posts.

Abilities

Dungeons and Dragons famously has six ability scores: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. Each ability has a value of between 3 and 18 for humans (originally the result of rolling three six sided dice), and gives a modifier of one for every two points above 10, and a modifier of negative one for every two points below 10.

While this is traditional, it's also old fashioned. If I were to redesign it, I would make the following changes: there is no difference between the ability score and the modifier. Instead, your score is your modifier, and your ability scores go from 0 to 5 (alternatively going below 0 for non-humanoid monsters).

But let's simplify it from six abilities to four. We need a good mix of physical and mental, and of abilities that represent strength and dexterity. So we have an ability for physical strength: Fortitude. And an ability for physical dexterity: Agility. But we also need an ability for mental dexterity: Mind. And finally one for mental strength: Will.

So we have our four abilities. Fortitude is a mixture of Strength and Constitution from D&D. It represents physical toughness and endurance, as well as physical fitness and muscle strength. Agility is most like Dexterity from D&D. It represents flexibility, accuracy, and muscle memory. Meanwhile, Mind is a good match for D&D's intelligence, and maybe the part of Wisdom that relates to noticing things and paying attention. It represents mental adaptability, quickness of thought, reasoning, and recollection. Finally, Will matches for both Charisma and the part of Wisdom that represents willpower. It's force of personality and stubbornness.

When creating your character, players start with 6 points to distribute among their four abilities, and can't put more than 3 in any one. So you could do 3-3-0-0, 3-2-1-0, or 3-1-1-1, and still put a three in your primary stat.

The problem with D&D is that the abilities are not created equal. Almost everyone needs Dexterity (for their armor class), and Constitution for the hit points. But not many characters need Intelligence. Usually you can get by with one specialist for that. And Strength can be dumped by a surprising number of builds, including combat builds relying on Dexterity. For that matter, only one skill depends on Strength. (And none depend on Constitution, but you still need the HP.) But a total of five skills depend on Wisdom.

I'd like to try to balance things out a bit better, with four skills for each ability, for a total of 16. I'd also like to have a few specializations available for each skills, which grant a bonus similar to expertise, but which can be tailored to fit the campaign.

Design Thoughts

Aside from the abilities, I'll need to consider the secondary stats, such as defense and hit points, and how those are derived. Here's my initial thinking:

• Chance to hit depends on Agility, whether done with a bow or a sword or a spear
• Damage depends on Fortitude, whether done with a bow or a sword or a spear
• There may be some exceptions, with significant downsides. A dagger may depend on Agility for both damage and hit chance, but it doesn't do much damage. A firearm or crossbow may not depend on Fortitude for damage, but they have long reload times.
• I base this at least partially on the fact that firing a bow requires a good bit of strength, which isn't reflected in D&D.
• Defense (AC) depends on a combination of Mind and Agility (probably the maximum for most people, but some unarmored fighting styles may let you add these).
• Health (HP) depends on a combination of Fortitude and Will. I'll probably sum these, as I favor a fairly high starting HP.
• Spells can target any of these defenses.
• Spellcasting can depend on Mind, Will, or both. I think it will probably be both for the pure spellcasters (Mind gives accuracy, Will gives damage), but may work differently for half-casters and others who have more stats they need to raise.
• Many D&D skills can be combined. Lore will cover many kinds of knowledge. Investigation, Insight, and Perception may be covered by one Mind skill. Persuasion and Intimidation can be one Influence skill, and Performance and Deception may fall under the same skill. Specialization can give bonuses to certain sub-skills.
• Rather than expertise, we may have the concept of specialization. That grants a +3 to a skill in a specific situation. When the Performance skill is used for a musical instrument, you may have a specialization.  Or a con artist may have specialization to his Performance in weaving a convincing lie. I'm thinking that each background may grant a specialization, as well as a skill.
• I plan to apply degrees of success to everything, including attacks and spells. Getting a higher degree of success does more damage, or has a stronger effect for a spell.
• For weapons, there will be no dice rolls for damage. Instead you add a fixed number between 0 and 5 representing the weapon damage to your Fortitude, and multiply that times your degrees of success to determine how much damage you do.
• I haven't decided whether spells should have the caster roll, or the target roll, or both depending on the spell. When the caster rolls, the more degrees of success, the better for the caster; when the target rolls, the more degrees of failure, the worse for the target.

Skills

So let's summarize the skills I have in mind:

• Fortitude Skills
• Athletics - Running, jumping, swimming, climbing, all the things athletes do.
• Labor - Farming, mining, digging pits, anything requiring long hours of backbreaking labor. From clearing collapsed tunnels to building a fortified camp, you'd be surprised how often this comes up in adventuring. And when you're not adventuring, there's always a need for strong backs.
• Survival - Weathering harsh conditions, trekking long distances, and rousing from little sleep to do it again the next day. Includes finding shelter and water as you travel.
• Steering - Sailing a ship, driving a vehicle, or riding a horse all require physical work to steer the vehicle or animal where you want to go.
• Agility Skills
• Finesse - From pick-pocketing to swapping the Gem of Doom for a fake while no one's looking, anything that requires fast hands falls under Finesse.
• Stealth - Moving quietly, keeping to shadows, and slipping through crowds unseen. All of these fall under stealth.
• Acrobatics - From balancing on a wire, to tumbling, to parkour, sometimes quick reflexes save the day.
• Crafting - Making potions, magic items, armor, weapons, food, baskets. They all require careful handling and exacting detail.
• Mind Skills
• Mechanics - Locks, traps, the strange gnomish contraption that looks like it's about to explode. Understanding how things work often allows you to take it apart, and maybe even put it back together.
• Observation - Noticing that you're being watched, spotting the secret door, hearing the beating heart under the floorboards, reading the expression of people and the tells of animals, all this falls under observation.
• Lore - You read. Therefore you know stuff. Maybe even a lot of stuff.
• Arcana - You're sensitive to the flow of magic, able to understand its currents and figure out what it does.
• Will Skills
• Concentration - Remaining focused despite distractions, and people trying to stab you--and sometimes succeeding.
• Influence - Someone said the core of diplomacy is to talk softly and carry a big stick. Whether it's threats or promises, you're good at getting what you want. Applies even when dealing with animals and others who don't share your language.
• Performance - Dancing, singing, playing an instrument, impersonating someone, or weaving a convincing lie. It's all about rejecting another person's reality and replacing it with your own. And if you're convincing enough, you can bring them along for the ride.
• Profession - One might think that having a professional job like scribing or shopkeeping would require one to have a sharp mind. One would be wrong. The primary requirement of such a job is to be able to keep focused, remain polite, and endure the petty slights of customers, bosses, and colleagues, day in and day out.

Specializations

In addition to skills, players also have specializations. Specializations come from both the class, and from the background. For example, a bard could have a Music specialization in Performance, or someone with the farmer background could have a Farming specialization in Labor. Specializations cover specialized use of skills, and provide a flat +3 on top of the skill bonus. The specialization itself describes what conditions that additional bonus applies in, but ultimately it's up to the DM whether you can use your specialization bonus.

Most of these specializations are described in the backgrounds and class features which grant them, but the DM may allow additional ones. Here are some possibilities to give some ideas:

• Athletics
• Swimming
• Climbing
• Running
• Jumping
• Labor
• Farming
• Mining
• Building
• Digging
• Survival
• Arctic
• Desert
• Mountains
• Forests
• Plains
• Cities
• Steering
• Sailing
• Rowing
• Riding
• Piloting
• Finesse
• Pickpocketing
• Legerdemain
• Stealth
• Nature
• Darkness
• Crowds
• Acrobatics
• Balance
• Stunts
• Traversal
• Crafting
• Alchemy
• Smithing
• Cooking
• Mechanics
• Locks
• Traps
• Steampunk
• Vehicles
• Observation
• Empathy
• Animal empathy
• Tracking
• Secrets
• Alertness
• Lore
• Medicine
• Religion
• History
• Nature
• Military
• Arcana
• Spirits
• Magic Items
• Curses
• Blessings
• Concentration
• Spellcasting
• Influence
• Animal Handling
• Oratory
• Intimidation
• Performance
• Dancing
• Music
• Acting
• Deception
• Profession
• Scribing
• Shopkeeping
• Innkeeping
• Trading

The Math

The fifth edition of D&D uses something called bounded accuracy. This limits how high rolls can get by keeping limits on the modifier, since the ability modifier maxes out at 5, and the proficiency modifier maxes out at 6, for a total of +11. Sort of. Then there's expertise, that doubles your proficiency modifier, spells like Bless and Guidance, that add 1d4, and Bardic inspiration, that adds d12. There's also the rogue's Reliable Talent, that causes any roll on the die below 10 to count as a 10. This means, at a minimum, a 10th level rogue with Reliable Talent and Expertise and Guidance and Bardic Inspiration, gets a total 25. On average, they would get about 35. That's a bit outside of bounded accuracy.

How would I control this? For one, I wouldn't grant expertise. I'll instead use specialization that will grant a flat +3 that doesn't scale with level. Second, abilities that would normally grant an extra die will instead grant an extra d10 roll that can replace one of the d10 rolls. (From the Weal pool, if we're using that. I'll probably make the pools an optional variant. If you're not using the pools, this is only limited by the class feature.) So while those will increase the average, they won't increase the maximum.

Otherwise, I'll scale similarly to how 5th edition does. Characters will receive bonuses to their abilities from their ancestry, background, and culture, but the maximum at 1st level for any ability will be 4. Until 10th level, the maximum will be 5, and until 20th, it will be 6. At 20th level, the maximum will increase to 7.

For the bonus from the skill, I think it will work similarly to proficiency bonuses in 5e, scaling with level. At first I was going to use the same scaling as D&D, 1 + level/4 rounded up. However, since I'm starting with a slightly higher ability modifiers, which increase to 7 rather than being limited to 5, and since my average rolls are higher by half (and my ~65% probability is about two points higher), maybe I'll just do level/4 rounded up. So skills will max out at 5, while ability modifier maxes out at 7.

Now, let's do some math, to determine what is Hard, Medium, and Easy for different characters. As a starting point, I consider something where someone has a 75% chance of success to be Easy, where someone has a 50% chance of success to be Medium, and where someone has a 25% chance to be Hard. Now with 2d10, we won't match exactly those numbers, but let's try to get relatively close. Players have a 55% chance to roll an 11 or higher, so we'll define that as our Medium. They have a 79% chance to roll an 8 or higher, but a 2% chance to roll a double 4 or double 5, which would effectively make those values below 8. So an 8 or higher will represent 77% chance of success. Meanwhile, a 2d10 has a a 21% chance of rolling a 15 or higher, +2% for the chance to roll a double 6 or double 7. So a 15 is a hard 2d10 roll, with a 23% chance of success.

So Easy, Medium, and Hard will represent a 77%, 55%, and 23% chance of success. Now let's define our characters:

• Novice: +0 to the roll. No matter the level, no character's trained in everything, and most character's will have one dump stat that remains at 0. When that character is first to make this roll, that's what he does it with.
• Average: +skill bonus to the roll. An Average character may have the skill, but doesn't necessarily have the ability score bonus.
• Gifted: +max ability modifier to the roll. A Gifted character has a maxed out ability modifier, but no training in the skill. Often, he'll be the best choice to make the roll.
• Skilled: +skill bonus + specialization bonus to the roll. Everyone has some specializations, but that doesn't mean that they're naturally talented with the ability. This assumes no bonus from the modifier, but Skilled can also represent someone with skill training and a decent modifier without specialization.
• Adept: +skill bonus + max ability modifier. Some things you're just good at. The Adept has both the max ability modifier and the skill bonus, but doesn't have specialization. You won't always have an adept for every skill, but you'll count yourself lucky when you do.
• Master: +skill bonus + specialization + max ability modifier. Then again, some people have it all. This is the best a character can get without relying on the fortune of Weal dice.

So first, let's consider what sort of rolls are Easy, Medium, and Hard for each character ability level. I selected levels 1, 5, 10, 15, and 20, since that covers are the skill bonuses and ability score maximums.

This gives us some idea of how easy it is to accomplish something. Even at level 1, what's Hard for the Novice character is Easy for the Master, and Medium for the Adept. A target number of 30, however, never ceases to be Hard, even for the Master. Such a task shouldn't be attempted without, at least, some favorable circumstances to help. And a 25 doesn't become Medium for the Master until level 20, and is still hard for the Adept.

In general, I think what's Medium for the Average character should be Easy for the Adept and should be Easy for the Master to achieve with an extra degree of success, and what's Hard for the Average character should be Medium for the Adept and should be Easy for the Master. I think this achieves that.

Where do attack rolls fit on this? Somewhere between Adept (characters are always skilled with their weapons, and usually max their attack roll as much as possible), and Master (as higher level characters tend to pick up magic weapons, that can give them a bonus close to the specialization bonus). Still, it's best not to design with Masters in mind, either for skill rolls or for enemies.

That does bring us to our design space for challenges. In general, I believe that an Easy target number should be Medium for the Novice character and Easy for the Average character, while a Medium target number is Hard for the Novice character and Medium for the Gifted character and Easy for the Expert, while a Hard target number is Hard for the Skilled and Medium for the Master.

Note that the standard 10/15/20 fits this fairly well for that level of difficulty. You can continue using that all the way up to high levels without leaving anyone behind, though it will start to become trivial to the Master, and pretty easy for the Adept. One way to handle that is to add higher levels of difficulty. Here's what I propose:

• Target of 10: Easy Difficulty. Anyone can do it, and most people have a decent chance.
• Target of 15: Medium Difficulty. It takes some luck for the novice to achieve, but every party should have someone with a decent chance of accomplishing it.
• Target of 20: Hard Difficulty. A novice can pull it off. Barely. Most parties will have difficulty accomplishing it.
• Target of 25: Expert Difficulty. If you have an Adept in your party, you might be able to pull it off, but it won't be easy.
• Target of 30: Specialist Difficulty. Only the very best in the world can pull it off, and even they fail more often than they succeed.

Note that something that is Hard difficulty is Expert difficulty to achieve with an extra degree of success, and Specialist difficulty to achieve with two degrees of success. Setting the target of 30 means that your party probably won't manage it. But setting it to Hard, means they have a small chance of getting three degrees of success. Here are the probabilities for each of the character ability levels to accomplish these difficulties at levels 1, 5, 10, 15, and 20.

Sometimes, though, you want to know what will actually be hard for your party. For that, I suggest balancing around Easy for Average, Medium for Gifted, and Hard for Skilled. I personally find this useful for skill challenges, so I know what my players are generally able to handle.

• Levels 1-4: 9 (Easy)/15 (Medium)/19 (Hard)
• Levels 5-8: 10 (Easy)/16 (Medium)/20 (Hard)
• Levels 9-12: 11 (Easy)/16 (Medium)/21 (Hard)
• Levels 13-16: 12 (Easy)/17 (Medium)/22 (Hard)
• Levels 17-20: 13 (Easy)/18 (Medium)/23 (Hard) 

This results in the following for the percentage odds of success (including the possibility of doubles, assuming I calculated them correctly):

Easy tasks remain Easy for the Average character (though they eventually approach Hard for the Novice character), Medium tasks fairly Hard for the Average character, and Medium to Easy for the Adept, and Hard tasks are Hard to Medium for the Adept, and approximately Medium to Easy for the Master.

Update (1/19/2023): Figuring out the math is of course an iterative process. I've created a new version based on two different assumptions: one where a Gifted (max ability, no skill) and Skilled (skill and specialization, no ability modifier) represent a more likely highest ability in the party, and one where the standard 10/15/20/25/30 are used throughout the game.