[K]

Yomi is, as far as I can tell, a proof of concept that with awesome magery you don't need real troops.

And they do that in spades. Toss down Darkness and your bakemono actually have 50% darkvision so they tend to come out even with real troops who don't. Toss down Army of Lead and you have the Protection to compete. Toss down army destroying spells and spells with high collateral damage like Falling Foo because your units are cheap when other people's are not. Boost the Str on your fire breathing units with Strength of Giants and Bloodlust and increase Precision with Wind Guide and you've got super-powerful AP fire attacks.

Heck, send in a Dai Oni with Soul Vortex and Fire Shield and Invulnerability and it doesn't even matter if he hits things....things just die.

The key problem is getting that Research. Your best mages are crap researchers, so there is a big loss of turn advantage in the beginning of the game.