Warning! Spoilers for Infinite Frontier #6 by DC Comics below
As the fight for DC's Multiverse reaches its boiling point, Darkseid just brutally murdered out one of his trusted allies, Machinehead, after he failed him. In Infinite Frontier #6, Darkseid's attempt to control the Omniverse through the Omega Lantern was thwarted. But, before departing, the evil ruler of Apokolips made sure to let DC's version of Iron Man pay the price after he didn't bring him promised victory.
In the current Infinite Frontier miniseries, Darkseid and Psycho-Pirate want to crack open the Multiverse and find and control what lies beyond it. After realizing the recently resurrected Roy Harper was vital to opening things up, Darkseid and Psycho-Pirate convinced Machinehead to help them in their quest in exchange for protecting his own Earth-8. Machinehead - DC's pastiche of Iron Man - served as a mole on the Justice Incarnate. Instead of assisting DC's Multiversal superteam from learning the truth behind Darkseid's plans, he actively sabotaged them to keep things hidden. After bringing in his own Justice Incarnate team to Earth-Omega, DC's version of Iron Man assisted Darkseid in battle with the greatest heroes in the Multiverse.
In Infinite Frontier #6 by Joshua Williamson, Xermanico, Romulo Fajardo Jr., and Tom Napolitano, President Superman attempts to save the Flash but is met with a powerful blast of energy from Machinehead. After being confronted by Thomas Wayne, Machinehead takes off his helmet and reveals his disfigured face. He tells the heroes he'll kill all of them and destroy Earth-0, as he hates the universe for Flashpoint and changing his own Earth-8 into a darker place. However, President Superman knocks Machinehead out cold after he becomes helmetless - and destroys the machine draining power from the Flash, ending Darkseid's attempt to break open the Omniverse. After Psycho-Pirate teleports to another crisis, Machinhead tells Darkseid they can still find a way to control the Multiverse. After saying he can fix the situation, Darkseid uses his Omega Beams to brutally kill Machinehead.
Machinehead served little use for Darkseid after his attempts to control the Multiverse failed. With no need to keep him around, Darkseid tied up loose ends and murdered the former Earth-8 hero.
It's quite the tragic ending for Machinehead, as DC's version of Iron Man only joined Darkseid so that he could protect his own Earth. Machinehead has seen endless tragedy since the events of Flashpoint, so while he ultimately broke bad, he did so to save his own reality from future destruction from events across the Multiverse. Darkseid has a reputation for being brutal, but killing Machinehead after offering him help, was ruthless, even for him. Infinite Frontier #6 is in comic book stores now.