Handling this ends up being tricky; the magic system for a fantasy game becomes a make or break proposition. I know that magicians have the baseline attack spell that they can use all the time (arcane/elemental bolt). Beyond this, they have a variety of spells. This list of spells should grow as the magician gets more powerful, with new spells added to the repertoire. So far, so good. However, how this plays out mechanically presents different possibilities. Here are some options:
Spontaneous Spells: In Mythweaver, you have a number of spontaneous spells available each turn. I could see magic working this way; you have any spell in your book available to you as desired, based on your bolt rating -1. With arcane bolt +5, you can cast up to 4 spontaneous spells per scene, casting any spell from your book. It is assumed that at +1, you can only cast your basic attack spell at will; you need more training to be able to cast other things. My original versions of the omni-weapon in the Resolute supers game worked under this concept: if you were an archer with a +5 bow, you got to take 4 trick shot effects each usable once per scene. I generally like this concept, although I’ve modified this out of the game with the use of applications, where you get to decide how many applications you want; you could use the same number of character points (20) to get a bow +7 with 2 applications as you would to get a bow +4 with 7 applications. They’re both viable ‘trick archer’ builds, with completely different philosophies behind them; the first one attacks mostly with his ‘basic attack’, using trick shots more sparingly, while the second probably leads off with his entire arsenal, going to the basic attack only after everything else has been used up.
Repertoire: You purchase individual spells as applications, only after you’ve added them to your book. Basically, the book gives you five spells to choose from as your character grows (costing 2 CPs each time you add a spell), which allows you now to master the spell, able to use it once per scene in a combat situation. Let’s say you start with charm, stun, life tap and boost might in your spell book. You can decide to spend 2 CPs to make any of these a spell you can cast once per scene. Optionally, you’d be able to use a resolve point to cast a spell that you don’t normally prepare as a ‘one time’ thing. The problem here is that resolve can then become a ‘pool’ for spontaneous spells, which I guess is okay… however, you can’t use resolve to then improve a spell and make it stronger, which becomes a good case for purchasing it and adding it to your repertoire if it’s going to be a regular thing. If I spend 2 CPs to get stun, I get to use it every scene, and I get to use a resolve point to add my intuition (for example) to the roll, sensing the exact moment my foe is most likely to be affected by it. If I don’t buy stun with 2 CPs but instead must use a resolve point to cast it, I only get to cast the basic form of the spell, and have no option to tweak it further with resolve. This seems to balance it out nicely.
I’m trying to design into the system that you can’t simply go into combat and use your stun spell 10 times. In fantasy literature, the caster doesn’t simply throw the same spell over and over again (except for the ‘basic attack’ bolt spell, which the game already reflects); special effect spells are generally only used once per scene. I want the game to emulate this dynamic. I would prefer that you work your opponent down, getting him to spend his resources (i.e. making sure he’s out of resolve) before you drop your stun spell on him (for instance).
However, a player trying to ‘manipulate the system’ to get to use stun 5 times has to not only buy stun but then spend 4 resolve points to do this; so the hero has invested 8 CPs to get this ability, and this assumes that all stuns are the basic variety that he cannot modify upward.
I could add a rule that multiple ‘special effects’ of a spell each scene offer diminishing returns. Once you have resisted petrification this scene (fighting off the effects of the gorgon’s gaze), you are more likely to resist it again; subsequent resist rolls against effect-based powers give you a cumulative +1 resist. I like this, although it is a bit of a complex concept for a relatively simple game. I don’t know if this particular rule gives the return on the investment of keeping track of it. Since many effects are one-shot tries anyway, and most foes you face won’t have resolve allowing them to refresh abilities that they’ve used, it isn’t likely to help the heroes as much as it helps their foes.
I probably need to play test some high-level fights to see if this will impact combat, or how much. If combats tend to run 10+ rounds, then I need to be wary of how multiple effects during a fight influence it; if combat tends to be over in 4-6 rounds anyway, whether you got to drop 3 charm attempts won’t matter as much.