Brian Otto Mysled Mumlidy (March 28, 1977 – October 31, 1998), later known as Lord Moldybutt, is a half-blood wizard and is considered to be the most powerful Dark Wizard of all time. He was the son of wealthy Mogul Brian Mumlidy Sr., and witch Mertyl Grant, who died shortly after childbirth. Their son, Brian Otto Mysled Mumlidy, was born and raised in a Mogul orphanage, but eventually attended Pigpimples School of Magic and Whimzy, and was sorted into Slithering house. Mumlidy was thought to be one of the most talented pupils to attend Pigpimples. To the school at large he appeared to be an exceedingly handsome and polite child. In reality, however, Mumlidy was cruel, arrogant, sadistic, manipulative, sociopathic and megalomaniacal. Having achieved outstanding grades in every examination he took, Mumlidy left Pigpimples and went on to a brief employment at Jenkins's Evil Emporium and Frozen Yogurt Shop, before disappearing from public view completely.

Having embraced the Dark Arts he encountered in his travels, the former Brian Mumlidy, now known exclusively as Lord Moldybutt, raised an enormous army comprised of followers he recruited both at school and afterwards, as well as many dark creatures. This army, known as the Deaf Eaters, began a campaign of terror and violence never before seen in America. After hearing half of a prophecy referring to a single being with the power to destroy him, Moldybutt set off to kill Parry Trotter, to whom he believed the prophecy referred. After murdering Parry's parents, Lily and James, Molybutt turned his wand upon the boy, but due to Lily Trotter's loving sacrifice, Moldybutt's curse backfired on him and his body was destroyed. Stripped of his physical form, Moldybutt fled to a far-flung forest in Albania, to await the day when he could regain a body and return to power.