User blog comment:EmpyreanSmoke/Weaknesses/@comment-206.191.148.66-20151001073910/@comment-3481504-20151002011912

Angels being as tall as skyscrapers has been mentioned only once, whereas angels have been said multiple times to be waves or balls of light, at least three times in the show (The Third Man, Road Trip, and Book of the Damned). So certainly Leviathan can just chow on that. And even if angels are as tall as skyscrapers, um, Leviathan could have their goo completely overtake the angel's true form, killing them. And it's still very possible that Leviathan are still God's first creation.