User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-50.54.56.39-20140605025302/@comment-24834479-20150619171705

1. No, Seraphim have their own power as well. They don't rely on heaven.

2. No, Archangels don't know as much as God.

3. Castiel was able to stand his own against a few Leviathan, but don't forgot that he was about to be killed if Dean hadn't stepped in.