In Norse mythology, Loki is a god or jötunn (or both). Loki is the son of Fárbauti and Laufey, and the brother of Helblindi and Býleistr. By the jötunn Angrboða, Loki is the father of Hel, the wolf Fenrir, and the world serpent Jörmungandr. By his wife Sigyn, Loki is the father of Nari and/or Narfi. And with the stallion Svaðilfari as the father, Loki gave birth—in the form of a mare—to the eight-legged horse Sleipnir. In addition, Loki is referred to as the father of Váli in the Prose Edda.
Loki's relation with the gods varies by source. Loki sometimes assists the gods and sometimes causes problems for them. Loki is a shape shifter and in separate incidents he appears in the form of a salmon, mare, seal, a fly, and possibly an elderly woman. Loki's positive relations with the gods ends with his role in engineering the death of the god Baldr. Loki is eventually bound by the gods with the entrails of one of his sons.