Maugrim (known by some records as Fenris Ulf) was a ferocious talking wolf and the head captain of the White Witch's Secret Police at the very end of the Long Winter. He was loyal to the White Witch.
Biography
Maugrim first led the raid of Tumnus' Cave where the Faun Tumnus was captured and his home left in tatters. Here, Maugrim left a letter to warn and intimidate others passing by, making an example of Tumnus. Maugrim encountered the human boy Edmund Pevensie while guarding the White Witch's Castle courtyard after Edmund mistook him to be a stone wolf.
He later spied on Aslan's Camp until being exposed by Susan Pevensie with the sound of her horn. Susan's oldest sibling, Peter, drew his sword and met Maugrim in battle while she fled into a tree. Although Peter at first missed Maugrim with his blade, while the wolf howled formidably, Peter successfully impaled Maugrim through the heart. The wolf captain died a few moments later, never ceasing his struggling.
His fate in the film is similar, although there are a few differences: Namely, Maugrim taunts Peter after the latter draws his sword inces away from Maugrim's face. Maugrim then pounces him only to be impaled on the sword, letting out a yelp as he dies. It is not specified whether his killing himself was deliberate or if Maugrim let his arrogance blind him.