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 The term slot is now outdated, though it's still the term used.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.