User blog comment:Varzan Deodinm Beldinm/Most Powerful Semblance?/@comment-10380701-20150109024314/@comment-10380701-20150109025516

Kiritsugu, actually. His spine bullet can pretty much cause any magus's mana to blow up in their faces.

Lancer's is more of a "wounds won't heal" curse thing, that pretty much nerfed Saber for a few episodes. He had to break one of his lance to nullify that.

Speaking more about Fate/Zero, Berserker's ability to weaponize everything (including a FIGHTER JET) sounds like a very effective semblance as well.