User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-86.159.50.151-20120508103555/@comment-3481504-20120508232836

Leviathans are capable of killing average angels, as "Reading is Fundamental" proves. Edgar, the Leviathan who demonstrated it, ripped out the vessels' hearts, which wouldn't have killed the angel. The angels can be in a dead host, after of audio consent, of course. He probably destroyed their grace. Or contaminated it, or something.