Loki Laufeyson is one of the Jotnar. Born to Fárbauti and Laufey, Loki became blood-brothers with Odin and lived with the Aseir. Loki is often labeled a trickster god or god of chaos. In the lore, Loki often uses unusual methods to get the task at hand done. From convincing Thor to dress as a woman in order to regain Mjolnir after it was stolen, to shape-shifting into a mare and giving birth to the horse Slepnir in order to help the Asier, Loki's methods to get the job done are always unconventional.
Loki is married to the goddess Sigyn. Together they have a son named Nari/Narfi. Loki also has three children with his mistress, the Jotun Angrboda. Hel the goddess ruling Helheim and the dead. Jormonger, the serpent which encircles Midguard and Thor's greatest enemy. And Fenrir the wolf giant whom, upon being tricked, bites off Tyr's hand and kills Odin in the great battle of Ragnarok.
Painting by Arthur Rackham, , 1911
Loki himself will take a large roll in Ragnarok. After angering the gods with killing Balder and insulting the gods at their feast, Loki is captured and chained in the entrails of his son Nari. His wife Sigyn holds a bowl over his head to catch snake venom but needs to empty the bowl as it fills. During that time the venom pours onto Lokis head, causing unbearable pain which causes Loki to scream out and thrash about until Sigyn is able to return with an empty bowl above his head. Eventually, all chains are broken which frees both Loki and Fenrir from their bounds. Loki sails the great ship Naglfar, teeming with the dead of Helhaim. The great battle of Ragnarok occurs and Loki dies at the hands of Heimdal while also slaying Heimdal.
With Loki essentially ushering in Ragnarok and much of his family directly participating in the final battle, some view Loki as evil or a dark god. While others see Loki as one who represents the outcast and those whom suffer from unfair judgment. Loki's children by Angrboda were taken from him due to their physical appearance, only then did he kill Balder, son of Odin, who made the judgment. Loki only goes into battle with the Asier at Ragnarok when he and his son, Fenrir, are chained and tortured. Loki also worked to help the Asier many times, even at his own cost. While we got the Asier into tricky situations, he did get them out and often with treasures. Freya's necklace Bringasmen, Thors mighty Mjolnir, the wall surrounding Asguard. And Loki did mother and birth Odin's mighty horse, Slepnir. No matter how one views Loki or his actions, he is a force of change and a major rule in Heathen lore.