Well, Toushirou will discover pretty quickly that he's just about useless for Phase 1, because although he's powerful, it's supernatural power, not physical. He was made for this phase, though.

First important thing to note for him is that he'll be in the air for this, because bankai. All his abilities are boosted this way because he's got a lot more spiritual power now. So launching giant ice dragons to freeze and pulverize vulnerable areas is totally a thing. Plus, he has a spell that blows stuff up now that I haven't had a chance to use in-game yet. If he's not freezing stuff, he can be blasting portions of the exposed crab to bits.

Oh, his bankai form can regenerate, too, so somehow getting one or both of his wings shattered in the air is something I'd like to do so he can discover that in dramatic fashion.