Iron Man is a superhero who wears a suit of armor. His alter ego is Tony Stark. Tony is a genius engineer and wealthy owner of a technology company. He possesses a wealth of powers through his powered armor suit. These powers include super strength, the ability to fly, durability, and a number of weapons. The primary weapons used by Iron Man are rays that are shot from the palms of his gauntlets. Iron Man gets his superpowers from his metallic suit of armor and other technologies invented by his alter ego. Tony built the Iron Man suit when he was kidnapped and suffered an injury to his heart. The suit was meant to save his life and help him escape.
Captain America has agility, strength, speed, endurance, and reaction time superior to any Olympic athlete who ever competed. The Super-Soldier formula that he has metabolized has enhanced all of his bodily functions to the peak of human efficiency. Captain America is the alter ego of Steve Rogers, a frail young man enhanced to the peak of human perfection by an experimental serum to aid the United States government's efforts in World War II. Near the end of the war, he was trapped in ice and survived in suspended animation until he was revived in the present day. Although Captain America often struggles to maintain his ideals as a man out of his time with its modern realities, he remains a highly respected figure in his community which includes becoming the long-time leader of the Avengers.
Thor is an extremely powerful warrior, and one of the strongest beings on Marvel Earth. His strength having often been compared to that of the Hulk. He also wields a magical hammer that is not only very powerful, but also has numerous mystical powers. Thor possesses the superhuman physical attributes of an Asgardian. The Asgardian god of thunder who possesses the enchanted hammer, Mjolnir, which grants him the ability to fly and manipulate weather amongst his other superhuman attributes.
The green-skinned, hulking and muscular humanoid, possessing a vast degree of physical strength. His alter ego Dr. Robert Bruce Banner, a physically weak, socially withdrawn, and emotionally reserved physicist. The two existing as independent personalities and resenting of the other. Following his accidental exposure to gamma rays saving the life of Rick Jones during the detonation of an experimental bomb, Banner is physically transformed into the Hulk when subjected to emotional stress, at or against his will, often leading to destructive rampages and conflicts that complicate Banner's civilian life. The Hulk's level of strength is normally conveyed as proportionate to his level of anger. Commonly portrayed as a raging savage.