Laufey was the ruler of the Jotuns (Frost Giants). In 965 A.D. he led a force of Jotuns against the people of Earth, but was eventually opposed by the Asgardians who had taken up a protective role over humanity. The two sides then waged war against each other, where Laufey was able to kill many Asgardians in the process, but despite wielding the Casket of Ancient Winters, Laufey and his people were beaten back, first from Earth, and then in their home realm of Jotunheim. Some point between this and his fight with Odin he has a son who he abandoned. During his final fight with Odin he was able to wound the All Father by taking out his right eye, but was ultimately defeated. Odin granted them mercy, but stripped the relic from them before declaring a truce and returning to Asgard. Laufey's abandoned son was soon found and taken by Odin who had hoped to unite their kingdom's one day.
Centuries later, several of Laufey's people breached the vaults of Asgard and attempted to steal back the Casket of Ancient Winters, thanks to Loki sneaking them in. This transgression incited the wrath of Thor, who in turn led a counter-attack against the Jotunheim, involving several of Thor's friends including Laufey's estranged son Loki. Laufey opposed them, but mindful of the ancient truce, and with the amassed forces of the Jotuns surrounding the sextet of Asgardians, he dismissed the intruders. Thor however, was baited by the heckling of a Jotun and attacked anyway. Although the Asgardians could easily outmatch the giants in isolated fights, Laufey turned the tide against them when he summoned his monstrous Frost Beast. He and his people beat the Asgardians back to their portal after Fandral was wounded by some ice shards launched at him by Laufey and stood ready to destroy them altogether when Odin arrived to intervene. With accusations of the truce having been broken from both sides, Laufey declared war and attempted to kill Odin with an ice blade but was knocked back and could only watch as Odin drew his people back to Asgard.
Some time later, Loki returned to Jotunheim and approached Laufey with a proposal that would reunite him with the Casket of Ancient Winters. At first Laufey wanted to kill him, but after learning that Loki was in fact the person who led them into Asgard he allowed him to speak. Loki stated that if Laufey were to kill Odin the casket would be returned. Accepting the bargain.
A bit later Loki allowed Laufey to enter Asgard with several of his people and move through the city unnoticed. Laufey entered Odin's bedchamber, knocked out the queen and one of his own men and was poised to kill the sleeping Asgardian when Loki double-crossed him, by disintegrating him with an energy beam from Odin's spear Gungnir in a surprise attack.
Laufey was a strong and proud ruler and a brave warrior. His main aim was to grant his people dominion over the other realms. When his attempt to conquer Earth fails thanks to Odin's intervention, he develops a deep hatred towards the Asgardians.
As all the Frost Giants, Laufey has an impressive stature, strength and stamina, and he possesses the ability to manipulate and create ice. His touch is poisonous to anyone but a fellow Giant. With his weapon, the Casket of Ancient Winters, he's able to freeze any opponent. He usually fights with an ice mace, but is able to use even swords and daggers.
- In the comics, Laufey is killed by Odin during their first battle. The Asgardian was at that time wielding Mjölnir, with which he crushes the Giant's skull. This has since been retconned.
- In Norse mythology, Laufey is the mother of Loki and Farbauti was his father. Conversely, the Ultimate Marvel Loki's mother is Farbauti and Odin is his biological father.