Morfin Gaunt

"Hissy, hissy, little snakey, Slither on the floor You be good to Morfin Or he'll nail you to the door."

- Morfin Gaunt in Parseltongue

Morfin Gaunt was a pure-blood wizard descended from Salazar Slytherin. He was the son of Marvolo Gaunt, brother of Merope Gaunt, and uncle of Tom Marvolo Riddle. He is described as having thick hair matted with dirt, missing teeth, and small dark eyes that stared in opposite directions.

Early Life
Morfin lived with his father and sister in a shack near Little Hangleton. Generations of inbreeding in the Gaunt family caused a defect in Morfin, rendering him mentally deranged and violent. He almost exclusively spoke in Parseltongue and frequently terrorized Muggles, including Tom Riddle Sr. after Morfin noticed his sister watching him with interest.

First Imprisonment
"She likes looking at that Muggle. Always in the garden when he passes, peering through the hedge at him, isn't she? And last night... Hanging out of the window waiting for him to ride home, wasn't she? But I got him, Father! I got him as he went by and he didn't look so pretty with hives all over him, did he, Merope?"

- Morfin to his sister about her infatuation with Tom Riddle Sr.

Morfin's violent behaviour eventually led to the Ministry of Magic pressing charges against him; Bob Ogden, head of the Department of Magical Law Enforcement, was sent to summon Morfin to a hearing, but the Gaunts resisted violently. When Ogden returned, he arrested both Morfin and Marvolo. Morfin received a three-year sentence in Azkaban while his father was imprisoned for six months.

While they were incarcerated, Merope married Tom Riddle, probably by using a love potion on him. She died soon after giving birth to a son, Tom Marvolo Riddle. Marvolo returned from prison to an empty house, and died before his son was released from Azkaban.

Second Imprisonment
Morfin's teenage nephew came to Little Hangleton to learn about his family in the summer of 1943. He met Morfin, who thought that this stranger looked "mighty like that Muggle", referring to the elder Tom Riddle. He told him of what transpired between the man and Merope, which infuriated Riddle Jr. to the point of seeking revenge. He went to the Riddles' home and murdered his father, grandfather and grandmother with the Killing Curse. He covered up his crimes by altering Morfin's memory, causing him to believe he was the killer. When the Ministry of Magic investigated the crime, Morfin freely admitted to it and was sentenced to life imprisonment in Azkaban. Tom also took the family signet ring from Morfin and wore it like a trophy at Hogwarts. It was eventually turned into one of his Horcruxes.

Albus Dumbledore sought Morfin out in prison, and in speaking to him, determined that his memory had been tampered with. Unfortunately, by that point Morfin was weakened to such an extent that he died before he could be exonerated.

Etymology

 * The name Morfin may be a homonym for the drug morphine, a highly addictive pain reliver, and may be related to the name Morpheus, the Greek god of sleep and dreams. Alternative, Morfin may be derived from the name Mervin, which comes from the Welsh mer, "marrow", and myn, "eminent".