Loki is one of the adopted sons of Odin in Norse mythology. He is the personification of cunning, trickery, and evil. Loki is the Norse God of Mischief and Lies. At one time he was also known as being the God of Fire. He has the power of changing his appearance (called Shapeshifting) and even gender, although he had to borrow Freyja's magical dress at times to change into birds. Once, Loki changed himself into a mare, and he bore the son of a horse. This eight-legged horse is called Sleipnir, and became the favourite horse of Odin. Loki also has many monstrous children, namely Hel, Fenrir, and Jörmungandr. He and his children became enemies of the gods in Ragnarok.
Loki is a murderer. He cut off the hair of Thor's wife, Sif, but then replaced it, he tricked a giant into building the defensive walls of Asgard, stole Freyja's necklace, helped Thor rescue his hammer mjolnir, gave the goddess Idunn to a giant, then rescued her, etc. He was blamed for the death of the god Baldur, using the blind god Hodhr's hands. In a poem called Lokasenna (Loki's Arguments), he insulted all the gods and goddesses. For this, he was bound to rock with the intestines of his son, until Ragnarok. Loki was punished many times in ways including; having a venomous snake drip venom into his eyes and he had his lips sewn together with a leather thong by the dwarves.