User blog comment:Varzan Deodinm Beldinm/Most Powerful Semblance?/@comment-25555436-20150108204355

So, you're asking, what if there was a villain that had a Semblance that allowed that villain to nullify someone's soul, as that's where Aura (and as such, Semblance) comes from.

Needless to say, that would be a 1-hit-kill against anything except the Grimm (who don't have souls) and most robots (except Penny). If the villain can't control it, it would quickly become a person of mass destruction. If it can, it's a big Story-Breaker Power.

A character like that shouldn't even exist, for many reasons, unless it has a very serious weakness that could explain how could someone powerful enough to insta-kill any adversary with a soul, be defeated.

Gilgamesh in Fate/Stay Night (and Zero) was powerful enough to destroy the world if he so wished, and even at 1% of his total power he could kick everyone's ass. How could he be defeated? His ego, which was soooo goddamn big he thought no one was worthy enough for him to use all his power.

But with a character like the one you're talking about, it's harder. Can you tell me a way for the protagonists to beat such a villain:

-Without making it seem like the villain grabbed the Idiot Ball.

-Without using Hand-Waves.

-Without making it seem stupid from a Writing PoV.

-And while making it seem actually believable instead of forced.