Death

Death is the eldest of the four Horseman of the Apocalypse and supposedly of a similar age to God, although he comments that neither one of them can remember who is older anymore. Due to his almost ageless existence, he considers most creation as inferior to him. He quickly comments to Dean that he is nothing but a speck of bacteria compared to him. This is a somewhat understandable view considering that Death is the being that will most likely end up reaping the soul of God himself.

He has the power to kill at will, as shown in the slow motion sequence upon his arrival in Chicago. When a man bumps into him, he is seconds later dead upon the pavement. It shows that Death is not necessarily bound by a specific code when it comes to killing humans.