After gaining the power of the Infinity Stones, Gamora sealed the souls of the universe within the Soul Gem. In order to incapacitate its inhabitants, she additionally folded the universe in half, merging every soul with another. This course of action accidentally resulted in the creation of Warp World, a pocket dimension where history was rewritten and adapted to the fused beings. Inside Warp World, Iron Man and Thor were merged together into Iron Hammer.
Stark Odinson was the son of Howard Odin, the Chieftain Executive of the Aesir of Asgard. While Odinson dreamed of serving the realm as an armor-clad warrior, the arrogance that stemmed from his immortality and godhood saw him denied of the right by Howard. Howard stripped Stark of his godhood and cast him out into the Earth with no memories of his past life, denying him the knowledge of his true heritage until he learned the pain and loss that came from being a human.
The amnesiac Stark awoke in a freezing storm, only filled with instinctive knowledge of unknown and advanced technologies. With his gifted intellect and drive, Stark went from nothing to the fifth richest man in Europe in the span of five years, building up a tech-industrial company under the name Sigurd Stark. Despite his riches and success, Sigurd was left haunted by his lack of memories, frequently driving him to drink. Traveling through the tundra while lost in thought, Sigurd was ambushed by a band of Dark Elves, and his leg was pierced with a poisoned arrow, leaving him crippled. The Elves spared the dying Sigurd and took him to aid their other prisoner Eitri the Weapon-Smith in building weapons for their forces. The two prisoners conspired to build a Stark a suit of armor to keep him alive and to escape protected from the Dark Elves' arrows, finishing just as the poison in Sigurd's systems had drained his body of any ability to move. The poison in Sigurd's heart was stopped by the runic inscriptions on the armor, and Eitri revealed a warhammer made of cold iron he had forged that would supercharge the armor and restore Stark's strength. Forcing his broken body to move and lift the hammer, a bolt of lightning struck the workshop, and Sigurd Stark rose once again, clad in the rune-inscribed armor of the Iron Hammer.