The Iron Man Mark 0 is the original armor Stark built in Afghanistan, which was improved upon his return to the United States with an onboard operating system, lenses, heating and cooling systems and rudimentary repulsor weapons. Stark used it to escape from Norman Osborn during the "World's Most Wanted" storyline, which ran concurrently with the company crossover "Dark Reign". Stark resorted to donning the Mark 0 after the brain damage he had inflicted upon himself in the course of erasing the Superhuman Registration Act database from his brain made it impossible for him to use any of his more complicated armors. The mentally incapacitated Stark and the Mark 0 armor were easily defeated by Osborn, who engaged Stark while wearing the Iron Patriot armor.