

One night, on the way to Guantanamo, the helicopter John was in was hit by lightning and crashed into the Caribbean Sea. John almost didn’t survive being stationed overseas. Looking the part, John lied about his age and joined the US Marines for a two-year tour of duty. He can apparently run at faster than normal speeds, as he was often seen overtaking a herd of buffalo. As part of his mutation, Thunderbird possesses over-sized lungs and an unusually developed respiratory system. Thunderbird's skin is also much denser than in ordinary humans, making him more resistant to physical injury. His muscle density is distributed in such a way as to greatly enhance the size of his arms, shoulders, and thighs. This is a result of his mutation making his muscle tissue much denser than that of an ordinary human.

As a teenager, Proudstar discovers he possesses the mutant abilities of superhuman strength, speed and resistance to injury. John Proudstar was born into an Apache tribe in Camp Verde, Arizona.
