How does one makes costs for their magic system without being arbitrary and breaking your own rules? (More info on post)
To be more specific. Usually, many stories have a magical energy resource that can be used a certain amount of times at once before it’s “spent”. My system, at least for ‘normal’ human mages (irrelevant in this context), uses the same thing.
But what I’m worried about is the following: there aren’t clear limitations on the reserves.
How much ‘Mana’ a fireball would cost? and how proportional to its size the cost would be? I don’t know how many “magic energy units” an individual has exactly, and this worries me, because not having numbers can make mana something completely arbitrary that I can use as vaguely as I want and break the rules without anyone knowing the better
Which, might work for some stories, but it’s not really something I like that much.
How do I avoid making characters run out of mana without making it feel like I’m pulling cards out of my ass, how do I measure the distance between a fledgling mage and a master wizard?
How do I make sure that a character casting 10 fireballs is the right amount, instead of 20, or 100?
Or what about other spells, what is the cost they should have?
Do I make an internal grading system of magic? Like, “heat+ size + power = magic cost” but I don’t show it to others and make it just my own writer notes?
But wouldn’t this just make the story a litRPG that’s pretending to not be a lit RPG?