Professor Remus John Lupin, Order of Merlin, First Class, (10 March, 1960 – 2 May, 1998), also known as Moony, was a half-blood wizard and the only son of Lyall and Hope Lupin. He was afflicted with lycanthropy during his childhood, as Fenrir Greyback's revenge against Lyall. He attended Hogwarts School of Witchcraft and Wizardry and was Sorted into Gryffindor house. During his school years, he was one of the Marauders; best friends with Sirius Black, James Potter, and Peter Pettigrew. Together they created the Marauder's Map. After Hogwarts, Remus and his friends joined the Order of the Phoenix and fought in the First Wizarding War. However, Pettigrew betrayed James and Lily Potter to Lord Voldemort and Remus lost all of his closest friends in various ways by the end of the First Wizarding War, though he and Sirius Black later reclaimed their friendship.

Remus taught at Hogwarts School of Witchcraft and Wizardry as Professor of Defence Against the Dark Arts during the 1993–1994 school year. He was also a teacher of Harry Potter, James's son, whom he taught how to conjure a Patronus, but resigned after Severus Snape revealed to the public that Remus was a werewolf. He fought against the Death Eaters once more in the Second Wizarding War, during which he lost his friend Sirius. In 1997, Remus married fellow Order member Nymphadora Tonks and had a son, Edward Remus "Teddy" Lupin. Remus fought at the Battle of Hogwarts, during which his wife was killed by Bellatrix Lestrange. Remus was also killed by the Death Eater, Antonin Dolohov, during the same battle in 1998. However, he briefly appeared again through the Resurrection Stone for Harry, along with James, Lily, and Sirius in 1998.

"It is the quality of one's convictions that determines success, not the number of followers."
—Remus Lupin.