Gladiator by Philip Wylie

Born as the unintended result of his scientist father's experiments, a man grows up with superhuman strength, speed, and resilience that set him apart from everyone else; as he tries on roles as athlete, soldier, and protector, he repeatedly confronts violence, injustice, and the moral limits of physical power, ultimately finding that extraordinary abilities bring isolation, impossible choices, and a painful struggle to reconcile personal responsibility with a world that cannot accept him.

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