I think the closest thing I can think of relating to that would be Bang Shishigami from BlazBlue, who has limited amough of nails he can use. Where I doubt I would use Nitori, I think this is interesting, having either option to use her energy sparingly (Bang can use nails to throw "kunais" or create bumpers to bounce off, each costing only one nail normally ) or if in a pinch, just unleashe all the energy you have for a lot of damage (Bang can use all of his nails to create a rain of nails for a lot of hits and damage).
Right, although Bang's stock resets every round. Maybe Nitori's does too and I'm misreading so far. I wonder if Nitori will also have an attack that empties her entire remaining stock for big damage like Bang does?
Actually it implies that she can't use some of her attacks if she lacks energy for them. Let alone reduced power.
Right, it seems clear that you can't use what you can't pay for, but I'm not clear on if the actual strength of the attacks is supposed to be effected as well.
Between Futo growing in strength over time, Nitori eventually becoming unable to use certain attacks/possible gradually getting weaker, and Miko's power level potentially fluctuating significantly, this game could have some bizarre matchups and interactions. Looking forward more and more to seeing how it all fits together. It's shaping up to be quite a complex game.