User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-98.113.182.208-20120512155723/@comment-3045936-20120513134235

The Levianthans have been confirmed as older only in the series by Sera Gamble when she was incharge and also by Ben Ellund as he was one of the people that came up with Eve and Purgatory for season 6. As for stronger that was never talked about.