Loki is one of the more famous figures in Scandinavian mythology, thanks to his mischievous nature. He is the trickster of the Norse gods, constantly upsetting the balance of the world and relations between the gods. Unfortunately for Loki, he took his pranks too far, and ended up chained to a rock until the end of the world.
Many traditional mythologies have a trickster god, who often facilitates change, as well as undertaking heroic actions to save other gods or mortals. In the beginning, this was Loki's role among the Norse gods. He is the son of two giants, Farbauti and Laufey, although he quickly tricked his way into the pantheon of Norse gods, called the Aesir. His presence was not always welcome: Loki was known to invade parties that he had not been invited to, demanding food and drink.
Loki has an assortment of children from a variety of goddesses, thanks to his three wives and wandering nature. His children include Jormungand, the Earth circling serpent, Hel, the underworld goddess, and Fenrir the giant wolf. These three children are prophesied to play an important role in the end of the world, known as Ragnarok. One of his more famous children is Sleipnir, an eight legged stallion that Loki actually gave birth to while in the form of a mare, and gave to Odin as a gift.
In addition to making trouble, Loki also sometimes assisted the gods with finding valuable tools, such as Thor's hammer. He also used his craftiness to get several members of the Aesir, including Freya, out of tight spots. The two companions most frequently seen with Loki were Odin and Thor, who often benefited from Loki's clever tricks and manipulations. Loki, of course, sometimes turned the tables on the two gods, embarrassing them in front of the other Aesir.
While living among the gods, Loki's tricks ranged from silly to sometimes cruel. In addition to being a trickster, Loki is also known as a shape shifter, and sometimes takes on the form of other animals or people in the stories told about him. His chameleon like nature allowed him to get away with a wide variety of pranks on the gods, sometimes with the unwitting assistance of other deities.
Loki took his trickster nature too far, however, when he was involved in the death of Baldur, the god of light. To punish him, the other gods chained him to a rock in the world underneath a giant serpent who continually drips venom that causes Loki to writhe in agony. According to Norse tradition, this is what causes earthquakes. When Ragnarok arrives, Loki will be set free to wreak havoc on the world once more.