Dawn Heart

A fragment of concentrated nuclear fuel was embedded in Shen Yuan's heart. He's not dead. His heart became a miniature nuclear reactor. He can charge a gun - turning a piece of scrap metal into a railgun that can penetrate an armored vehicle with one shot. He could recharge the mecha - an energy-deficient mecha roared to its feet again. In an apocalyptic world where one battery can be exchanged for three lives, he himself is the ultimate resource that everyone competes for. But he knew the nuclear fuel in his chest was killing him. Five years. He still has five years at most.