User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-3045936-20120505183038

I think now bashed of what I saw. That Levianthans are immune to at least regular Angels, and now holds strength at least equal to them. And when he killed the Angels black ooze came out. So maybe that has something to do with it too and not something as simple as just being stronger.