Diavalo

Mammon had just lost a bet and Lucifer was too busy to punish him so he sent him to Diavalo's castle and while he was there Diavalo offer him a deal, if Mammon behaved Diavalo will buy him anything he wants but if he doesn't behave himself then Diavalo will punish him, as a part of the deal Mammon has to help Diavalo with his Ruts