Mammon

Mammon, Prince of Greed, Former Prince of Hell.
First appeared in Season 2.
Mammon's first appearance was when Simon Prince made a deal with him and began turning Clearwater into a kind of Prince-flavoured Pottersville.
Fionn Corvin banished Mammon back to Hell by sacrificing his Boba Fett keyring and finally his beloved Deadbeat Hearse.
Fionn won the hearse along with his keys and Simon Prince's soul back in a poker game with Mammon.
Mammon was involved in the conspiracy with Beelzebub, Asmodeus and Satan to ally with Erebus.
He was allowed to escape with his life because he was not involved in the murder of Lilith and because Fionn was tired of bloodshed at that point after killing Murmur and Satan and many Stalkers in the Burning Man game.