Diamondhead was mutated by a diamond-powered laser while attempting to steal some precious gems. He developed a hard, diamond-like body that was superstrong. He used his new abilities to enhance his criminal career.
Diamondhead was created by Marv Wolfman, Sal Buscema and Tom Palmer in 1976 and first appeared in The Man Called Nova # 3.
Mayor Story Arcs
After being defeated by Nova, he forms the criminal gang Terrible Trio with Condor and Powerhouse. After Condor is defeated by the Sphinx, Diamondhead allies with the Sphinx and Doctor Sun. Along with his allies, Nova, and the Champions of Xandar, Diamondhead goes to Xandar on Nova's spacecraft. Then while he was a member of the Champions of Xandar, he betrayed them and Nova Corps to the Skrull Empire. Which resulted in the death of a member called Crimebuster. The being known as the Stranger kept him captive in his laboratory world for awhile. Diamondhead is left to float in space.
Later, Diamondhead was seen as a prisoner on the Stranger's laboratory world. He escapes and returns to Earth.
After the Stamford incident
Following the Stamford incident, the identities of the New Warriors were publicly leaked, including Nova's. Diamondhead uses this information to locate Nova's parents' house and patiently waits until his nemesis comes home. When Nova returns to Earth after the Annihilation War, Diamondhead attacks him. Nova easily defeats Diamondhead and takes him back to prison.
Diamondhead was last seen fighting Nova after he returned to Earth following Annihilation. He said he'd been waiting for revenge for years against Nova, and had been waiting for him to return to Earth. However, this battle was brief, and with Nova's powers, he easily shattered one of Diamondhead's hands (although he said it would grow back in a few hours).
Powers and Abilities
Diamondhead's body is basically one large diamond, making him incredibly strong and incredibly resistant to injury and harm. According to Nova, he can regrow destroyed limbs, given time. It is unknown how much he can heal.