User blog comment:EmpyreanSmoke/Leviathan VS Archangel/@comment-188.4.147.206-20140826134718/@comment-3481504-20140827215445

Wrong, sir. Leviathan aren't innately immune to angelic power, they have to consciously and willfully activate it, seen by the fact that Castiel was able to use his super strength by briefly holding Dick in place. It was also said in "Blood Brother" that distance is factorial in it working. So, if Michael was on the moon, his powers would still work and he could totally eviscerate a Leviathan by flooding it with fire.