Remus Lupin was a Marauder, one of the best friends of James Potter's. He was bitten and turned into a werewolf by Fenrir Greyback as a child.
He was a prefect at Hogwarts School Of Witchcraft and Wizardry, and later the Defense Against the Dark Arts teacher.
As an adult, he was a member of The Order Of The Phoenix, husband to Nymphadora Tonks, and father to Theodore "Teddy" Lupin. He was killed at the Battle Of Hogwarts along with his wife, orphaning his child who was only around a month old at the time. He made Harry Potter his son's godfather at the Shell Cottage.