At the age of nine, he lived with his older cousin at the Marris Stead. During one of Sylvanas Windrunner's visits to the stead, Stephon came across Nathanos and Sylvanas talking and stared in astonishment at the ranger-general. Sylvanas asked him if he wanted to be a ranger when he grew up, but Stephon replied that he wanted to be a knight. Nathanos told the boy to leave, but not before Sylvanas gave him a gold coin and told him to keep it until he was old enough to buy his first sword.
As an adult, Stephon joined the Argent Crusade as a paladin. He kept the coin that Sylvanas gave him for years, even after Stratholme fell, and the Scourge ravaged Lordaeron. He hoped that Nathanos had somehow survived and often asked about him, but was met only by shrugs and awkward silence. When he began hearing stories of a creature called the "Blightcaller" haunting the old Marris Stead and hunting down Alliance heroes, Stephon feared that it had murdered Nathanos and he vowed to take its head. He only learned of the fiend's true nature and what had become of his cousin when he overheard two refugees from Darrowshire whisper the being's true name. On that day, Stephon threw the ranger-general's coin into the river. For some time, Stephon often patrolled near the Marris Stead, taking down no small number of Forsaken in the process. Sylvanas, now the Banshee Queen, could have ordered her dark rangers to end his life, but "never got around to that".
Shortly before the Burning Legion's third invasion, Stephon was captured by Sylvanas and brought to a secret chamber in the Undercity, where he was tied to an altar. She was about to have her val'kyr perform a ritual that would reshape and repair Nathanos' rotten, torn body and flesh, but it required a sacrifice of flesh, flesh akin to his own. When Nathanos was brought to the chamber, the cousins briefly exchanged bitter words, and Nathanos realized that part of him was proud that his cousin had fulfilled his childhood dream of becoming a paladin. The val'kyr that had accompanied the Banshee Queen and her champion to the chamber proceeded to place herself between the human and the undead and began chanting guttural words in an ancient tongue, flashes of blue and gold pulsing from her hands. Nathanos lost his senses for a time, his world exploding in fire and pain. When Blightcaller's wits returned, he found that he had become stronger than before and no longer was decayed and withered. When he looked into a mirror, he noticed that his new face was not entirely his own. He then noticed that the second ritual table was empty save for a bit of ash and oily residue stains. When he later walked through the halls of the Undercity, Nathanos felt a touch of regret.
He may have been related to Marshal Marris.