User blog comment:EmpyreanSmoke/Leviathan VS Archangel/@comment-27006668-20150923141417/@comment-26992577-20150924233420

It was already mentioned by EmpyreanSmoke's Supernatural writer friend, that Leviathans can kill Archangels, while Archangels can't kill Leviathan. She also said that not even Jesse, who could kill an archangel with a single word, coul kill a Leviathan. That makes sense, God probably made them so resilient in other to use them as soldiers against The Darkness.