User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-3481504-20111223215216

Here's the strength-scale, going from strongest to weakest, and goes something like this...

God > Death > Michael > Lucifer > Jesse > Godstiel > Gabriel > Raphael > Eve > Seraphim > Angels > Pagan Gods > Leviathans > Azazel > Lilith > Samhain > Crowley > Red-Eyed demons > Cupids > Normal demons > Monsters > Humans

As far as the other three horsemen go, they're natures having separate consciences, making them indestructible, but where they would fit on this scale, I don't know. See, archangels aren't at all acceptable to their powers, and fully-powered angels aren't affected by their influence, which would make them lower than celestial beings, in a sense. Same goes for demons inside vessels, seeings as they can't get sick, nor to they require any kind of sustenance