User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-190.92.7.204-20150612220839/@comment-5961531-20150614111340

I'd agree with that. Lilith was definitely afraid of it, but perhaps only because it would still have been painful, even if it couldn't kill her. Abaddon took care to disarm Dean when the latter had an Angel blade, even though it apparently couldn't have killed her (which I'm still skeptical about by the way), so it might be the same situation with Lilith and the Demon knife.

But deadly just means the ability to cause death. If we go by definition, then Sam and Dean are two of the most deadly beings alive, but are they the most powerful? No. Far from it. I do understand where you're coming from, but I personally can't accept Cain as the most powerful. I just don't think he's done enough.

Just because Cain smote some Demons does that mean Lilith couldn't? Lilith has shown the same white light ability only shown by higher level Angels, the same ability used to smite Demons. I'm pretty sure Lilith could kill Demons the same way. Lilith's could even be considered more effective and powerful, considering all she has to do is raise her hand. Cain had to touch the Demons faces to smite them.

Please don't misunderstand me, I'm not debating how Cain can be killed. I agree that an Angel blade wouldn't have worked. I can accept that the First Blade was the only thing that could kill him, but that alone doesn't make him more powerful.