The Godkiller was a powerful weapon created eons ago by the Aspirants to battle the Celestials, and it was being stored in a Dyson Sphere, but it had been stripped of some of its components. The Recorder 451 learned of its existance and spent hundreds of years looking for it and its parts, with the last of them being the Heart of the Voldi.
451 planned for the Godkiller to be used as a nuclear detterent of Earth, as it believed humanity had the potential to bring universal peace in the future, and 451 needed a pilot as the autopilot of the Godkiller was extremely clumsy. 451 genetically engineered the unborn child of Howard Stark, as the most suitable patient to become the Godkiller’s pilot. Years later, 451 met the son of Howard, Tony Stark, now the superhero Iron Man, and told him about his secret origin, ultimately bringing him to the Dyson Sphere and forced him to become one with the armor. When 451 discovered Stark couldn’t pilot the Godkiller, thus that everything he did was worth nothing, he decided the giant armor couldn’t fall in anyone’s hands and activated a mechanism which transported it to another dimension, with the intention to take Stark with it. Before the dimensional shift began, Stark managed to use 451’s tech to hack the armor and escape before it was too late. It was later revealed that Tony discovered he couldn’t pilot the Godkiller because he wasn’t the baby 451 had genetically engineered, but the programmed pilot was his long-time lost secret brother Arno.