User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-3481504-20120516180343/@comment-5110811-20120518035553

God Cas was immune to angel weaknesses because he had leviathans in him. They are older than souls and are virtually unkillable. They leviathans didn't give him power. They only provided immunity and were slowly poisoning him. It has nothing to do with the 30 million souls he absorbed. Cas is a mutated angel on par with Michael and Lucifer. He isn't beyond them. He's either slightly stronger or equal to Michael and Lucifer.