Laufey (Earth-199999)

Laufey was the leader of the Frost Giants of Jotunheim for over a millennium. In the year 965, using the Casket of Ancient Winters, he led a Jotunn invasion of Midgard, but their offensive was countered by an Asgardian army led by King Odin. The Asgardians fought the Giants back to Jotunheim, where they were dealt their final defeat. Odin claimed the Casket, as well as Laufey's infant son Loki to raise as his own. The Giants and Asgardians lived in a tense peace for over a millennium, until 2010, when Loki magically opened a path from Jotunheim to Asgard's treasure room, where lay the Casket. Three Frost Giants entered Asgard, but were instantly killed by the Destroyer after attempting to steal the Casket. The event nonetheless created unrest in Asgard, and soon a small group of Asgardians led by Odin's son Thor, along with a deceitful Loki, took to Jotunheim to demand answers. Laufey claimed that there was a traitor in their midst, incensing Thor and starting a battle. The Asgardians were outnumbered in spite of Thor's considerable power and fled to the Bifrost, where they were met by an arriving Odin. Odin pleaded with Laufey to forgive his son's foolish actions, but Laufey refused. War declared, Odin blasted the Giants back and allowed himself and the others passage back to Asgard.

This was all part of Loki's plan to seize power in his home realm, which bore fruit after his brother Thor was banished to Midgard and Odin fell into his Odinsleep. Loki returned to Jotunheim, this time to negotiate with Laufey as king of Asgard. Loki offered him the Casket in exchange for the Giants coming to Asgard and killing Odin as he slept. Laufey agreed, and when the time came, he was indeed given passage to Loki's realm. As Laufey stood over Odin's prone body however, Loki betrayed him, vaporizing him with his magic staff. Loki had engineered Odin's attempted assassination in an attempt to "save" him and be seen as a hero. Laufey's death at an Asgardian's hands might have caused an even larger-scale war, but the Bifrost was destroyed by Thor soon after, and Loki cast himself from Asgard, cutting off all standard passages between the two realms.