with her ultimate ability, it says she can't be defeated, but that doesn't mean she can't be brought down to 1hp. The protection for all other allies is really nice, but its a useless ability unless the other allies are still alive because she can't do anything in that stance and will just get beat up. If i'm going against her, if she goes into that stance, i'd just beat up on her until she's almost dead and then as soon as she's out of it she dies very easily. Kylo's ultimate makes it so he can't be defeated AND can't take damage. much better than just merely not being able to be defeated IMO