The Prose Edda

There is yet one who is numbered among the asas, but whom some call the backbiter of the asas. He is the originator of deceit, and the disgrace of all gods and men. His name is Loke, or Lopt. His father is the giant Farbaute, but his mother’s name is Laufey, or Nal. His brothers are Byleist and Helblinde. Loke is fair and beautiful of face, but evil in disposition, and very fickle-minded. He surpasses other men in the craft of cunning, and cheats in all things.