Quote Originally Posted by shinta|hikari View Post
So reshaping is what allows Sukuna to counter, but just plain soul damage does not?
In order to use reshape, Mahito's soul has to contact the target's soul, which allows Sukuna to contact him back, and why Mahito can't use his Domain Expansion around Yuuji.

I don't know how Black Flash works. But it's probably just Rasenganing someone with curse energy.