User blog comment:EmpyreanSmoke/Supernatural Q&A/@comment-168.169.25.92-20150924215559/@comment-3481504-20150924223434

As I already explained on the 'Leviathan VS Archangel' blog, Leviathan are much, much stronger than humans, or any earthly creature, all demons, all monsters, all spirits, all deities (except for God, of course), and all angels which would include even archangels.

They're sooo strong, that they're called the 'supermen of monsters.' To put it into perspective for you, Dick or Edgar could pretty easily each take out Gabriel and Raphael at the same time on their own. Every single time someone's gone up to a Leviathan and "won," they always had help. For example, in Survival of the Fittest, Dean needed Cas to kill Dick, and Cas needed Dean there too. Or in Slash Fiction, Dean, Sam and sheriff Osborne all needed each other to take down the Leviathan. In Shut Up, Dr. Phil, Dean and Sam needed Don to paralyze Chet to stop him from massacring them. In the Purgatory scenes, Dean and Cas needed each other to take down Leviathan.

Point is, Leviathan could tear archangels apart.