The Mad Goblin by Philip José Farmer

A brutal, pulpy thriller in which two engineered supermen—one a feral, jungle-raised avenger and the other a brilliant, weaponized adventurer—discover they are pawns of a clandestine cabal that has manipulated their lives. Forced to confront experiments, betrayal, and their own violent conditioning, they clash and occasionally cooperate in a globe-spanning quest to expose and destroy the secret society that made them, blending lurid action, conspiracy, and a dark, satirical take on pulp-hero mythology.