Who does Iron Man fight in the first movie?

In the first Iron Man movie, Tony Stark fights Obadiah Stane, also known as Iron Monger. Stane, his mentor and business partner, ultimately betrays Stark and seeks to use Stark Industries' technology for his own gain. The climax of their confrontation occurs when Stark dons his Iron Man suit to stop Stane, who has built a larger version of the suit to challenge him.