Steve is a demon who lives with his same-sex partner Tony in the same apartment building in which Sam, Sock, and Ben also currently live in.
He dies in the episode "Rebellion", after the Devil causes a building to collapse on him.
In the episode "Cancun", he appears to Sam through visions, implying that he is now an angel and in heaven. He then appears to Tony right before Sam was buried alive, telling him that he was an angel and proving to Tony that just because Sam was the Devil's son doesn't mean he was evil.
When a baby is left behind by an escaped soul, Sam decides to give the child to Tony; who names the baby Stevie. Sometime later, a small cult is started based off him; as he was a demon who managed to redeem himself and ascend into Heaven. Steve appears to a man named Gary through Tony's tv. In The Devil and Sam Oliver, Steve is a guardian Angel to a crazy, accident prone girl named Mary Pat, who works at the Work Bench. He breaks Sam's hand under orders from heaven, causing Sam to lose the contest with the Devil to get him out of his contract and Andi's soul. At the end of the episode Steve gets his wings.