I think Yukari would be infinitely more dangerous as a Persona. Doubly so with Kaguya and Mokou if they manage to grant their invincibility to their masters.
Well there was a good number of Persona that gave you several Immunities making it almost seem like immortality. Though when you think about it, Kaguya and Mokou wouldnt give their master immortality, they dont "block" damage out, they can still be hurt. If anything, Kaguya and Mokou would give Invigorate to their master, like say, 200 hp per round or something.
