Harry Harrison 
Planet of the Damned 

Dis was a planet, a wasteland, a world of death where living was dying and dying was much better than living.Dis was a scorching desert, its people crude, barbaric, backward and miserable – and they would become seven million blackened corpses unless Ihjel stopped the H-bombs. But Ihjel had forseen his sudden death, and only one man could take his place – Brian Brandd, Champion of Champions and master of a secret power.