@TheFake: Okay, I realized what the one thing that was still making me hesitant is.

My one remaining concern is that, since anyone who hears him cast his two biggest spells is affected, this means that if player characters hear them they have nothing they can really do but stumble around blindly.

@Dead Cruiser: I think you misunderstood, I wasn't suggesting an affinity for youkai as an idea, I was using it to say "Spirit" as an affinity is a bad idea. It would basically be an affinity dealing with an entire class of widely differing beings and I really have no idea how it would function when applied in the same way other affinities are. And there is actually onmyodo in this but I didn't think it was immediately relevant to the RP.

And, well... there's really no "over-dimension" for spirits? ^^; There [i]is[/i] a different plane of existence but that won't conceivably be appearing in this RP. Ki in an of itself I never really considered to exist in this setting, I guess astral projection might be a thing, I'm not actually sure what the "aura" would be other than a mana signature that's possible to pick up on if you know what to do for this though.