Iron Monger (real name: Obadiah Stane) is a supervillain and co-founder of Stark Industries along with his partner Howard Stark. His armor's weapons are exactly like those of Iron Man, except his are bigger and more powerful; however, the suit lacks repulsor beams.
Stane first appears in the film welcoming Tony Stark back from Afghanistan, where he was held hostage by terrorists. When Tony announces at a press conference that Stark Industries will stop manufacturing and selling weapons, Stane refuses to allow this and betrays Tony, trading with those same terrorists, the Ten Rings, behind his back. When Tony's assistant Pepper Potts finds out about Stane's actions and contacts the secret organization S.H.I.E.L.D. to bring him in, he steals Tony's ARC reactor, a device embedded in his chest that powers his suit and keeps him alive, and uses it to complete a suit he was working on based on Tony's earliest suit design, the Mark 1. Stane, outfitted in the armor, attempts to kill the S.H.I.E.L.D. agents and Pepper, but Tony, who revived himself using the ARC reactor from the Mark 1, engages him and manages to defeat him by activating the giant ARC reactor in his building, killing him.