RIKI-OH 力王2 「滅びの子」 (1990)

Riki finds himself in the town of Misaki, dotted with illegal nuclear power plants and run by a religious fanatic military organization called "God's Judgment." He is taken prisoner and made to fight in gladiatorial matches in a sprawling arena. He finds his brother, whose special powers have given him the name of "Savior," but his reunion with his resentful sibling turns sour rather quickly.