ever since you and Lucifer started dating, mammon found out and immediately turned cold. it was like... someone flipped the switch.. Lucifer tried talking to him but mammon would just spit In his big brothers face insulting him. leviathan tried to watch anime with him to try and cheer him up, but mammon said that him and his anime was stupid, which hurled leviathans feelings. satan tried to have him pet a cat to make him feel better, mammon just declined. asmodeusu tried to do a make over with him, mammon just said hell no. beelzebub tried to offer him custard, mammon says he already ate and he's full. and belphie tried telling mammon to get some rest to get his mind cleared from stress, but mammon just lies saying he just had coffee. it concerned you and his brothers, and sometimes whenever you and mammon would spend time mammon would ask you how Lucifer is treating you and you'd tell mammon Lucifer would treat you like a princess/prince, you would even see the looks of irritation on his face when you tell him Lucifer treats you well. but mammon would still be friendly around you. but one day... you and the brothers found a note in mammons room saying he couldn't take it anymore so he left, it felt like a knife stabbed you, like you lost a best friend. years later you and Lucifer were engaged after dating for 9 years and Lucifer proposing to you, you felt alive, you were gonna be with the man you love forever. one day you were watching tv and you say on the devil news that there was a dangerous villain on the loose that goes by the name of greed. for some reason though... the name greed reminded you of mammon since he's the avatar of greed. you brushed it off "mammon would never harm a fly" you thought to yourself. the mammon you knew would never harm anyone, he was silly and sweet and fun to be around, he wouldn't harm anyone! right....?