In the new universe, every person had a new, but complete history- including a childhood, youth and adulthood- and no memory of their original universe. So Iron Man had to be reborn- and he was, this time not as a result of a booby trap in the Far East, but a direct encounter with the newly born Incredible Hulk. His chest pierced by shrapnel from a crashed helicopter, Stark had no choice but to do an experimental exoskeleton (Project: Prometheus Rising) which had cost the life of one of his closest friends before. He had to keep wearing the chest plate constantly to keep his shredded heart beating thereafter.