In the future, a new Batman was needed to save Gotham once again. His name was Terry McGinnis, and unto a new Batman came many new villains. One that would be a personal, and personally deadly, villain was Blight.
Derek Powers was a businessman who was never afraid to cut corners and make back end deals. When this led to the death of Terry's father, he tried to expose him with the help of an elderly Bruce Wayne. When Bruce didn't like what Terry wanted to do, Terry stole a new Batman suit and tried to stop Powers himself. After a fight, Powers was affected by a powerful nerve gas, and though he lived, he was never the same again.
He is a literal nuclear meltdown waiting to happen, and emits so much radiation, he's dangerous just by being in his vacinity. His condition makes him close to immortal, as he survived being pinned on the bottom of the ocean for months, and got out the hard way. By waiting.