It's well known that Iron Man is a powerful hero in the main Marvel Universe, but in the Ultimate Universe Tony Stark is Marvel's most dangerous weapon. In this parallel Marvel dimension, this member of the Avengers follows up the traumatic events of Ultimatum with a retelling of the famous Armor Wars storyline and the result is explosive.
The original Armor Wars storyline by David Michelinie and Bob Layton saw Tony Stark learn that his Iron Man tech had been stolen and sold to his rivals who allowed criminals to repurpose his designs for their own armor and vowed to take them down. In the Ultimate Armor Wars by Warren Ellis and Steve Kurth, Tony Stark has survived the near apocalypse of Ultimatum to find his company in ruins and his fortune dwindling. Returning to the demolished graveyard of New York, Tony seeks to rebuild his company while keeping secret technology from ending up in the wrong hands. He is too late as he discovers Justine Hammer, the superpowered daughter of his old rival Justin Hammer, and the techno thief called the Ghost have already infiltrated Stark Enterprises, the latter escaping with Remnant 242 after a brief fight. While Justine agrees to help Tony, she reveals Stark technology is being illegally sold on the black market with criminals eagerly purchasing it for their own designs.
After traveling around the world and facing new and reimagined villains, Tony eventually faces the series overarching villain, the cyborg remains of his grandfather Howard Stark, Sr. Having financed Ghost, Justine, and created Tony's latest Iron Man-like opponents, Howard reveals he not only wants Tony to help upgrade his suit but that he wants him to open Remnant 242. Exhausted, frustrated, and hurt by Justine's betrayal, Tony complies and Remnant 242 is revealed to be the severed head of Tony Stark from another Earth, specifically Earth-242 which he found while exploring other dimensions with Fantastic Four's Reed Richards. While everyone is caught off guard, Tony is calm throughout his explanation of what Remnant 242 is and does until he literally the last man alive.
Ultimate Armor Wars treads on familiar ground regarding Tony Stark's threat to the world while not being afraid to bring new and disturbing examples to the table. Throughout the story, Tony wears himself out traveling to deal with upgraded black market dealers, international villains with their own Iron Man suits, and even foreign authorities who planned to use the tech to quell aggressive protestors. Although Tony takes down each opponent, it's a reminder that his mainstream counterpart has dealt with for years, Iron Man knows that any good idea will be repackaged, repurposed, and sold to the highest bidder. When the contents of Remnant 242 are revealed, Tony explains the head came from a Marvel world completely on fire and while it is a version of him, its technology is different and more advanced. It continues to operate although its host is dead, running a self-defense mechanism that kills any machinery it comes into contact with. Having already learned this the hard way, the protected Tony watches his grandfather, Ghost, and Justine die sudden and violent deaths, leaving him alive and alone.
If anybody understands the quote "heavy is the head that wears the crown", it's Tony Stark. While he has the intelligence, money, and worldwide celebrity of being Iron Man, he deals with extraordinary situations that often put his life at risk which weigh especially heavy when the weight of responsibility falls on you. The sole survivor of Ultimate Armor Wars is left drinking alone at a bar with the dangerous head of his multiversal counterpart, crying over the fact that the only thing he's protected the world from is himself.