Warning! Spoilers to Infinite Frontier #4 below!
DC's version of Iron Man used Marvel's seemingly endless crossovers to justify his sudden betrayal, mocking the grandiose series of events at the same time. The character called Machinehead hails from Earth-8 which is essentially DC's version of Marvel complete with heroes, villains, and inevitable tragedy. This deformed yet intelligent version of Tony Stark helps the Justice Incarnate monitor and deal with threats throughout the multiverse. In Infinite Frontier #4, he betrays his team, revealing that he's done so to prevent any other cataclysmic crossovers like the ones that destroyed his world.
Created by Grant Morrison and Ivan Reis in Multiversity #1, Machinehead hails from a world that was protected by the Retaliators which Machinehead was a member alongside other pastiches of Marvel's Avengers. While it appeared his world had already been destroyed, Machinehead worked alongside Calvin Ellis, the President Superman from Earth-23, helping him solve complex problems as seen in Infinite Frontier: Secret Files #1. Machinehead works alongside other heroes in the multiverse as a member of the Justice Incarnate who, following the events of Dark Nights: Death Metal which restored the multiverse, investigate the mystery surrounding the return of Thomas Wayne, the Flashpoint Batman
In Infinite Frontier #4 by Joshua Williamson, Paul Pelletier, Jesus Merino, and Xermanico , Machinehead has been studying the fragments of a ship containing Thomas Wayne that were scattered throughout different worlds. While the working theory is that someone was secretly transporting people across the multiverse, Machinehead was tasked with finding their absent member Barry Allen. When the clues set Justice Incarnate on the path to Earth Omega, Machinehead suddenly attacks his teammates, knocking them to the ground while preparing the Hall of Heroes for some new arrivals. When asked why, he reveals that he doesn't want to destroy the multiverse but simply keep the DC universes separate from each other, " no more crossovers between worlds".
Machine Head has the appearance, powers, and intelligence of Tony Stark but he's a version of Iron Man who has simply had enough. While crossovers have become an occasional yet still regular event in comics, Machine Head's world experienced one of Marvel's Incursions, an event when two universes are set to collide with each other. While heroes from either world fight in vain to prevent this or destroy the other world so theirs can be spared, Machine Head essentially tells his unconscious teammates that his world lost. This loss is a not-so-subtle reference to the second Secret Wars, a 2015 event that destroyed and then restored the Marvel universe. He blames Earth-0 for this and believes the way to stop this from ever happening again is to keep the universe's separate and ignorant of each other and the multiverse overall.
It would appear that this version of Iron Man has switched sides, betraying the Justice Incarnate for what appears to be the Injustice Incarnate. Tony Stark may have done his fair share of questionable actions in the past but Machine Head has so much time in the suit, he's lost his humanity in the process. Like all villains, he's considered the morality of his decisions and deems them necessary to accomplish his goals. Although Secret Wars would have its share of consequences for the Marvel Universe, this Iron Man is so dedicated to his version of saving the multiverse, he'd work with the villains to do it.