In the philologist and fantasy author J. R. R. Tolkien's Middle-earth fiction, a warg is a particularly large and evil kind of wolf that could be ridden by orcs. He derived the name and characteristics of his wargs by combining meanings and myths from Old Norse and Old English. In Norse mythology, a vargr (anglicised as warg) is a wolf, especially the wolf Fenrir that destroyed the god Odin in the battle of Ragnarök, and the wolves Sköll and Hati, Fenrir's children, who perpetually chase the Sun and Moon. In Old English, a wearh is an outcast who may be strangled to death.
Through Tolkien's influence, wargs have featured in fantasy books by authors including George R. R. Martin, and in media such as video games and role-playing games.