Mark I: Captured by terrorists and forced to make weapons, Tony Stark instead built a suit of armor and escaped. The Mark I was destroyed on its maiden flight, but the parts were found by Obadiah Stane and used as a template for the Iron Monger armor.
Mark II: Stark's second, more refined attempt at armor was prone to icing, resulting in a near-fatal drop from the upper statosphere. The Mark II was temporarily upgraded to serve as James Rhodes' War Machine armor; it has since been reverted.
Mark III: Stark's first red-and-gold suit was used to combat terrorists in Afghanistan and unsuccessfully engaged twofighterjets. After it was heavily damaged in battle with Stane's Iron Monger suit, Stark did not attempt to repair it.
Mark IV: The Mark IV replaced the damaged Mark III, and is very similar in appearance. After it was discovered that the arc reactor in his chest was poisoning him, Tony abandoned the Mark IV, developing a new reactor and a new suit of armor.
Tony Stark: The genius son of industrialist Howard Stark, Tony was seriously injured by a bomb blast in Afghanistan. The shrapnel in his chest is held at bay by an electromagnet, powered by the same arc reactor that powers his many suits of armor.
Mark V: Collapsing into a box the size of a briefcase, the Mark V is portable and can be put on without robotic assistance. While durable, it still sustained massive damage from Ivan Vanko's energy whips in their Monaco street fight.
Mark VI: The Mark VI was designed to use a more powerful type of arc reactor made of vibranium. The suit survived a brawl with the Asgardian Thor, but it was seriously damaged when caught in a turbine while repairing the falling SHIELD helicarrier.
Mark VII: This armor was used to repel the invasion of Earth by the Chitauri. Deploying in a torpedo-shaped form, Stark merged with the Mark VII in mid-air, destroying several Chitauri transports before guiding a nuclear device towards their flagship.
Mark XLII: Stark's most high-tech armor, the Mark XLII is the 42nd suit to come out of his ironworks, and features independently mobile components that can be summoned and assembled with a mental command.
Pepper Potts: Virginia "Pepper" Potts was originally the personal assistant to Tony Stark in charge of managing his schedule, relationships and art collection. Briefly installed as CEO of Stark Industries, she is now Tony's business partner and love interest.