User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-98.207.51.174-20111001055220/@comment-112.200.212.230-20111120130521

Crowley can't help them fight the leviathans because crowley is no match from castiel and castiel is no match from the leviathans. Hence, Crowley is no match from the leviathans.... :)