Karl Lykos was born in the isolated mountain region of Tierra del Fuego. His father was a former sailor of simple means who became an explorer's guide, living in a cabin on the mountain range. Karl was born in that cabin and his mother apparently died in childbirth or shortly thereafter, leaving his father to raise him alone. Karl's father was a good-natured and honorable man, who wanted to save up enough money for his bright son to receive a full education abroad. As a consequence, he accepted guide-work, taking tourists and explorers along some of the most treacherous terrain in South America.
One fateful day, a pre-teen Lykos and his father were guiding the rich Herr Anderssen and his young daughter Tanya through the Tierra del Fuego mountains when little Tanya went missing from their party. Karl heard a cry down an isolated tunnel and ran through it to find Tanya under attack from pteranodons. As one of the southern most points of South America, Tierra del Fuego had a network of caves that connected all the way to Antarctica and the Savage Land. Karl rushed forward to defend Tanya from the creatures, fending them off with nothing but a stick. Although he was victorious and brought Tanya back to her extremely grateful father, Karl fell ill due to the scratches he suffered in battle with the pteranodons.
Herr Anderssen arranged for the best medicine and doctors for Karl, and the boy slowly recovered from his injuries. Karl's full recover did not come, however, until his faithful dog Jager lay his head on Karl's leg, and the boy instinctively absorbed the animal's life essence while touching him. Rejuvenated by the process just as Jager was weakened by it, Karl soon realized he had become an energy vampire, driven to steal life energy from other creatures. Karl believed the energy-draining was now necessary for his survival, although he may have merely been psychologically addicted to the rush of life energies. Whatever the case, Karl began a secret life of sneaking small touches of life energy from others whenever the opportunity arose.
Karl's father eventually passed away and Herr Anderssen demonstrated the depth of his gratitude by bringing Karl to America and raising the boy alongside his own daughter. Anderssen's gratitude had a clearly defined limit, however. As they grew into adulthood, Karl and Tanya fell deeply in love with each other, but Anderssen forbid their engagement. Despite his affection for Karl, Anderssen was set in old world beliefs about wealth and a man's duties; he considered Karl a poor commoner who wasn't worthy to marry his daughter. Although Tanya loved Karl and would have married him even without her father's blessing, the stinging rejection of Herr Anderssen made Karl obsessed with proving himself in the man's eyes and winning his daughter's hand by Anderssen's own rules. Karl left the Anderssen home in Scarsdale to attend medical school. He continued corresponding with Tanya via letter as he graduated with his doctorate and set up a practice of his own.
Unfortunately, Karl's addiction to life energy was hindering his long-term plans. Lykos stylized himself as a hypno-therapist, attending to patients suffering from the shakes and nervous energy. By hypnotizing his patients, Lykos then drained their bodies of excess energy, temporarily curing their afflictions while feeding his hunger. Unfortunately, Karl's hunger was growing stronger all the time and much of the profits from his practice went towards the development of an electronic apparatus designed to amplify the potency of the life energy he absorbed from his patients. Seeking alternative avenues, Doctor Lykos became a colleague and consultant for Professor Charles Xavier on mutant biology. It was Lykos' hope that his work with Xavier would lead him to genuine mutants to study and the hope that mutant life-energy would inevitably be more powerful than that of normal humans. After discovering Lykos was in his terms a "non-mutant variant," Xavier ultimately broke off their consultations.
Doctor Lykos eventually acquired his first mutant patient after Xavier's apparent death. Xavier's students, the X-Men, were in need of a physician to examine their injured ally, Havok. The X-Men found reference to Xavier's correspondence with Lykos in their mentor's records and brought Alex to Lykos for treatment. Eager to begin his work, Lykos excused the X-Men from his offices and strapped Alex into his electronic amplifier. The sheer power of the mutant life-energy he absorbed overwhelmed Lykos, as he began the final stage of his mutation begun decades earlier when the pteranodons infected him through his cuts and injuries. Lykos transformed into the world's first were-pterodactyl, a self-proclaimed force of evil that dubbed itself Sauron.
Reveling in his power, Sauron began looting businesses to gather the funding necessary to expand his research and prove Herr Anderssen wrong about his worthiness to marry Tanya. Sauron inadvertently cast blame on the mutant Angel when onlookers saw only a winged assailant during the crimes, leading the Avenging Angel to take to the skies and find his "impersonator." When confronting Angel and the other X-Men, Sauron learned his previous skills as a hypnotist had developed into an outright mesmerizing gaze. Unfortunately, he also learned that his power was finite and he exhausted his Sauron-power battling the teens. Before reverting completely back to Lykos, Sauron got a hold of Angel and hypnotized him into carrying Lykos to safety.
Back at his office, Lykos was surprised to find Tanya waiting for him. Tanya had grown tired of the distance between them and came to see Karl personally to convince him that her father's permission wasn't necessary for them to marry. Herr Anderssen had followed his daughter, however, and accused Lykos of being a charlatan with his hypnosis practice, still unfit to marry his Tanya. Despite Tanya's best efforts, Karl maintained that proving himself to Herr Anderssen was paramount before their relationship could proceed. The Anderssens left along with the civilian-attired X-Men, who had unwittingly come to collect Lykos' revitalized patient, Alex Summers.
Fuming over his encounter with Anderssen, Lykos tracked the X-Men and managed to get the drop on Lorna Dane, Havok and Angel again, fueling his transformation into Sauron with their collective mutant energies. Drunk with power, Sauron flew to Scarsdale with the intent to murder Herr Anderssen to remove him as an obstacle to Tanya's love. Sauron encountered the X-Men again during his attack, but also had a flash of insight. Lykos realized Tanya would never have forgiven him for the death of her father and also recognized the evil of his Sauron persona was more than he could stomach. Regaining his self-control, the ashamed Lykos flew across the continents until he reached his abandoned family cabin back in Tierra del Fuego. As he reverted from Sauron back to human, Lykos hoped to isolate himself from temptation, to prevent the evil of Sauron from resurfacing.
Unfortunately for Lykos' sacrifice, Tanya knew him well enough to guess where he fled to. With the X-Men following behind her, Tanya found Karl at the cabin. Weakened from his withdrawal from stolen life energies, Lykos panicked when he saw Tanya running towards him, believing he would not be able to stop his vampiric appetites from draining her dry of lifeforce. In desperation, Lykos threw himself over a cliff in an act of selflessness to protect Tanya, and only a sudden ice-wall projected by Iceman prevented Tanya from following after him. [X-Men (1st series) #59-61]
At Tanya's request, the X-Men traveled down the icy cliff side to find what happened to Lykos, unwittingly passing him on their descent. Lykos had landed on a small outcropping a short distance down and hid from the passing X-Men to continue his hermitage. He followed the icy slopes down into a cavern, which eventually revealed a passageway into the Savage Land. Finding some peace in the lost kingdom, Lykos made a home for himself on an isolated island in the middle of one of the great lakes. Finding the abandoned equipment from a long lost garrison of WWII soldiers, Lykos began modifying their primitive electronics to his own purposes. He intended to re-route geothermal energy from the magma flow beneath the island into a power source for his encampment. Lykos survived off of the life essence of surrounding animal life, keeping just enough to sustain himself without transforming into Sauron.
Lykos' peace was eventually shattered by the arrival of Iceman months later, having journeyed back into the Savage Land in pursuit of his teammates on a different mission. Bobby Drake was weakened and amnesiac by his ordeal crossing the Drake Passage by himself, and so Lykos cautiously nursed Iceman back to health while guardedly concealing any information about himself or Drake to avoid being found out. This balancing act was upset when Magneto himself arrived, eager to take advantage of Lykos' geothermal work. Magneto's attack injured Lykos and threw him off balance, so that when Drake raced over to help him, Lykos could not resist feeding off of Iceman's mutant energies, transforming himself back in Sauron.
Sauron confronted Magneto, trapping the Master of Magnetism in his hypnotic stare. Fearing how powerful Sauron would become once he fed off of Magneto's power, the restored Iceman and his arriving teammates, Havok and Lorna Dane, separated the two. A three-way battle unfolded which led to the geothermal equipment being destroyed and a weakened Magneto trapped in an inadvertent volcanic eruption. Magneto tried to form an alliance with Sauron, but the Pterodactyl Man dismissed the mutant villain, seemingly leaving him to his death, tumbling down a lava chute. As the X-Men were distracted by trying to save Magneto, Sauron caught their gaze and wiped their memories of the encounter, sending them on their way to maintain his privacy. [X-Men: The Hidden Years #6-7, 9-12]
Lykos regained dominance soon after, now that mutant life-energies had left the Savage Land again, and lived in peaceful isolation while feeding off of small animals. However, one day he unexpectedly came across the re-emergence of the Sun God, Garokk, when his priestess Zaladane transformed an unwilling host to hold his power. Garokk single-handedly ended the Sheenar invasion of the Savage Land before planning his own rule of the lost jungle. Ka-Zar of the Savage Land was injured during the routing of the Sheenar, and Lykos found the jungle lord and helped him recuperate. Together, they formed an alliance with the Fall People to oppose Garokk's tyrannical grip on the Savage Land.
Luck seemed to be with the revolutionaries, for the X-Men had returned to the Savage Land after escaping another conflict with Magneto. Lykos failed to contain his appetites, though, and assaulted a bathing Storm for her life energy. The unexpectedly powerful energies taken from the mistress of the elements triggered Lykos' transformation before he could contain himself, and Sauron stalked the Savage Land once more. Drunk with power, Sauron used his hypnotic abilities to turn the X-Men against each other before trying to snare the newly-arrived Colossus. On a hunch, Cyclops ordered Colossus to transform to his steel form and the sudden explosive release of bio-energy from that transformation overloaded Sauron. Unable to feed from the backlash, he reverted back to Karl Lykos, and Ka-Zar arrived to arrange peace between the X-Men and Lykos. After Garokk was defeated, Lykos parted as friends with Cyclops and the X-Men, choosing to remain in seclusion in the Savage Land to avoid further temptation as Sauron. [X-Men (1st series) #114-116]