While on an expedition to Tierra del Fuego, geneticist/psychologist Dr. Karl Lykos was bitten by a mutated pterodactyl from the prehistoric Savage Land which infected him with a genetic virus that forced upon him the need to drain the life energy of others to survive. Lykos eventually became a hypnotherapist, and constructed a device to help drain his patients’ energies. After absorbing the energy of the mutant Havok, Lykos was transformed for the first time into the pterodactyl-like Sauron, named after the arch-villain of Tolkien’s The Lord of the Rings novels. He battled the X-Men, but soon began reverting back to Lykos and fled. Later, as Sauron, he attempted to kill his own lover Tanya Andersson, but was again opposed by the X-Men. As Lykos, he became despondent over his behavior, and after she and the X-Men found him he ran over a precipice and was believed dead.
Lykos survived and journeyed to the Savage Land where he once again fought the X-Men as Sauron. For a time, as Lykos, he proved an ally to both the X-Men and Ka-Zar. Ultimately reverting to his Sauron form, he usurped the leadership of the Savage Land Mutates and opposed Ka-Zar, Spider-Man, and the X-Men. Defeated, he reverted to human form again and was reunited with Tanya. Later, he and Tanya were captured by the Toad who was seeking recruits for a new Brotherhood of Evil Mutants. Forced to absorb Tanya’s energy (possibly fatally), Lykos was transformed into Sauron again and joined the Brotherhood in opposing first X-Force and then X-Factor. After the Brotherhood disbanded, Sauron returned to the Savage Land and, with the Mutates, opposed various members of the X-Men. Capturing Cyclops and Havok, Sauron drained their energies which caused him to mutate further. Jean Grey engaged Sauron telepathically, allowing Lykos’ personality to force his alter ego’s psyche in making a suicide leap into the abyss of his own mind, thus reducing Sauron’s physical form to a pure, animal-like state.
Sauron’s suppressed persona eventually returned and he sought out the X-Men. Defeated once more, he was subsequently recruited into the new Weapon X Project as a field agent, but after the Project was torn apart by internal feuding he was incarcerated in the maximum security superhuman prison the Raft. The Mutates engineered a breakout of the Raft’s other inmates as a cover for Sauron’s escape, and he returned to the Savage Land where he and the Mutates became involved with a rogue S.H.I.E.L.D. faction illegally stockpiling Vibranium. Opposed by Wolverine and a new Avengers team, Lykos was stabbed by Wolverine before transforming into Sauron. The fight was interrupted by S.H.I.E.L.D. troopers led by the Black Widow (Belova), who shot Sauron in the head. The stress of his wounds caused Sauron’s powers to mutate further, but he was still defeated and remanded into S.H.I.E.L.D. custody. They in turn handed Sauron back to Weapon X.