I like creating various magic systems, but keeping it simple can be challanging.
The idea I have is for exponential power costs for spells that can take days to recover from using high level spells yet allow nearly limitless use of cantrips and such.
Basically, run on spellpoints and treat the spell level as the exponent for how much mana it takes to cast the spell. So sl 0 costs 1 point, sl 1 costs 10 points, sl 2 costs 100 points,... sl 9 costs 1 billion points.
I like what the concept represents, but using it directly like this would be quite ridiculous and painful to track.
One of the aspects here though is to allow the lowest level spells to be used freely without worry about the cost, but as the sl goes up, it becomes an increasing problem. I also want low to mid spells to be recovered from quickly to perhaps a day, but have higher spells take days to a week to recover from, and the closer to empty the caster runs, the more difficult it becomes to cast any spell.
Of course, getting multiple casters together to cast a spell to spread the cost among them should be viable but this also raises how powerful of a spell that can be cast.
And of course, I want the difficulty of casting to be separate from the mana cost. (will be using some form of casting check to determine the effectiveness of the spell)
So I'm hoping some of you can help me figure out a way to represent this without trying to keep track of millions of spell points.
You might want to consider Spheres of Power.
I like those but they aren't what I'm looking for.
Specifically, the concept of making higher spells take days to recover from casting, yet still allow lower spells to be cast almost at will.
I want it that using low level magic is common, using mid-level magic is a strategic choice, and high level magic is something to use only when desperate.
I have the theory that this can be a counter to the spiral of death (when taking damage imparts penalties making it easier to be hurt), by making it so that in combat the best abilities are actively avoided but available when the lower abilities just can't win.
But to test my theory, I need a good setup that utilizes it, but the spell-points in the millions just seems a bit ridiculous and so I'm looking for a more elegant solution.
These are some interesting ideas, not quite what I'm looking for but worthwhile for some. Good for ideas though that first option link has a broken link in it.
How about this,
Roll an Energy check when a spell is cast. A d20 plus casting modifier minus strain. The dc is spell level times three.
If the check fails by more than five, strain is gained equal to twice the spell level and the spell fails (vitalizing variant; roll a fort save or fall unconcious), the spell fizzles and strain is gained equal to spell level. If the check succeeds by five or less, the spell is cast but one strain is gained.
If strain equals or exceeds the casting stat score (vitalizing variant; use constitution score), then no more spells can be cast until strain is equal to or less than the casting stat modifier.
Strain is recovered at a rate dependant on type of caster. Full casters recover a point every 8 hours, medium casters every 12 hours, and low casters every 24 hours. Spontaneous casters are treated as a rank higher. Full spontaneous casters recover a point of strain every 6 hours.
Multiple casters can work together by spreading the strain among the group. All casters attempting make an energy roll treating it as if the spell were 2 levels lower. Any who fail take 2d6 damage and must make a fort save (Dc 10 + twice the spell level) or collapse unconcious.
The vitalizing variant can expend hp to reduce strain. The energy roll dc can be reduced by 3 points by rolling a hit die and losing that much hp. You can only roll hit die you have and all must be rolled at once. (i.e. if Bob is multiclass with 2d6 and 2d8 in hit dice, then Bob can only roll a max of 2d6 and 2d8 to reduce the dc by 12)
Additionally, in the vitalizing variant, half the con score in strain imparts the fatigued condition which can't be removed until strain becomes less than half the con score, in a likewise manner, once strain exceeds the con score, the exhausted condition is suffered until strain becomes less than the con score.
In the vitalizing variant, once strain has reached the point the caster can no longer cast spells, the caster may still cast spells if they spend at least a number of hit dice equal to the spell level using the above rules for reducing energy dcs.
This is just a rough idea. What do you think?
What's wrong with a little risk? You have to roll and take that risk with sword-swinging, so why should magic be risk free?
The caster isn't balancing both mana and hp. Hp isn't normally affected by spellcasting. It is just an option for taking a greater risk when they are out, or almost out, of mana. Balancing mana and hp implies the player has to handle effects on both of them most of the time which isn't true. (though healing spells do need to be checked to make sure you can't heal more than spent.) The idea is that you can avoid burnout (being unable to cast magic) or to cast while in burnout by risking your own life force. It isn't intended for a caster to be casting magic from health on a regular basis.
The blackfang link (the link to the original 3.5 material) is broken, but what I could read on it does not fit what I'm trying to achieve, and being playtested doesn't change that. It works for what it was designed for, and yes it is worth looking at, but it won't achieve what I am wanting.
I am not looking for time limited casting nor ritual casting. Rather I'm looking for slower mana recovery so casters do not simply start each day with full resources, this is tied to mana and not what spells were cast. And for what amounts to magic teamwork which certainly doesn't need to be ritualized.
The ritual mechanic you suggest makes mages working together in combat a non-possibility, which is counter to what I'm going for. The idea of raising spell level gets awkward (given that spell level determines the dc to cast, among other factors), but it having a higher caster level is interesting (only works with using the d20 spell setup though, and I've been looking at various setups).
The biggest factor is what the system is trying to achieve. Clearly I haven't made what I'm trying to achieve very clear. Hopefully the above comments help readers understand what I'm going for.