Sirius Black

Sirius Black (1959 – 18 June, 1996), also known as Padfoot or Snuffles in his Animagus form, was a pure-blood wizard, the older son of Orion and Walburga Black, as well as the older brother of Regulus by slightly over a year. Although he was the heir of the House of Black, Sirius disagreed with his family's belief in blood purity and defied tradition when he was sorted into Gryffindor instead of Slytherin at Hogwarts School of Witchcraft and Wizardry, which he attended from 1971 to 1978.
As Sirius' relationship with his relatives deteriorated, he gained lifelong friendship in James Potter, Remus Lupin, and Peter Pettigrew. The four friends, also known as the Marauders, joined the Order of the Phoenix to fight against Lord Voldemort and his Death Eaters during the First Wizarding War. Sirius also became the godfather of Harry Potter, the only son of James and Lily Potter. When Pettigrew betrayed the Potters to Voldemort, Sirius sought to exact revenge on Pettigrew. However, Pettigrew was able to frame Sirius for his betrayal of the Potters, the murder of twelve Muggles, and the staged murder of Pettigrew before Sirius could accomplish this.
Sirius was sent to Azkaban, and after twelve years became the only known person to escape the prison unassisted by transforming into his Animagus form of a massive black dog confused with a "Grim." Sirius exposed Pettigrew's treachery to his old friend Remus and his godson. After Lord Voldemort returned in 1995, Sirius rejoined the Order. He was murdered by his cousin Bellatrix Lestrange during the Battle of the Department of Mysteries and subsequently cleared of all charges by the Ministry of Magic.
He briefly appeared again through the Resurrection Stone on the 2 May, 1998 for Harry, along with James Potter, Lily Potter, and Remus Lupin. Harry later named his first son James Sirius Potter after him.