User blog comment:ImperiexSeed/ARCHANGEL or LEVIATHAN!/@comment-84.178.153.12-20120513115525/@comment-3481504-20120513164144

Nope, I'm right. You just at a misunderstanding, so you're the one who's wrong. I meant besides Death's personal Scythe, an Archangel's blade is the only weapon that can kill them.

As regrading begins with the capability to kill them, God and God can, easily. And Cas, while wielding all of Purgatory's souls, can kill Gabriel or Raphael.

Technically, though, he said, "Leviathan beats Angel", not "Leviathan best Celestial, or something like that.