This Cyber Leader, designated Cyber-Leader One, was the leader of the Cybermen of a parallel Earth following the destruction of the Cyber-Controller, their creator, John Lumic. It served as the initial leader of the army of five million Cybermen which had crossed from their parallel Earth to the Earth of the Doctor's universe, resulting in the Battle of Canary Wharf.
After their defeat at the hands of the Preachers, resulting in them being sealed in their Cybus factories, (GAME: Cyber Assault) the Cybermen took advantage of the time they had as humanity debated what to do with them, infiltrating their universe's Torchwood Institute. They found a crack in the universe, caused by the passage of the Void Ship, and a combined force of five million Cybermen were able to travel from their dimension into the Doctor's. The Cyber-Leader led an advance guard of Cybermen, establishing a base in secret inside the Torchwood Tower at Canary Wharf, while the rest of their army infiltrated the planet in the guise of benign ghosts of deceased humans. After two months (three years in parallel Earth time), the Cybermen upgraded several Torchwood employees into drones in order to take control of Torchwood's ghost shift and finalise their invasion. It was at this time that the phenomenon was discovered by the Tenth Doctor, who came to Torchwood and, after deactivating the drones, traced the Cyberman signal and uncovered the advanced guard, who, under the command of the Cyber-Leader, proceeded to reveal themselves as they wrested control of the ghost shift from Torchwood. With the ghost shift increased to 100%, all the ghosts suddenly appeared in their true Cyberman form, occupying every landmass on the planet with the intention of upgrading all of humankind. The Cyber-Leader confirmed to the Doctor that they did not create the Void Ship, being beyond their technology, having only followed in its wake. (TV: Army of Ghosts)
Simultaneously, a quartet of Daleks, the Cult of Skaro, had exited the Void Ship with the Genesis Ark. The Cyber-Leader, detecting the appearance of unknown technology sent Cyber Units Ten-Six-Five and Ten-Six-Six, leading to a confrontation with a single Dalek, who swiftly exterminated the two Cybermen after refusing a proposal of alliance. In response, the Cyber-Leader addressed the Cult of Skaro's leader, Dalek Sec, via a communications channel, warning that the Daleks had declared war, or as Sec retorted, "pest control", against the Cybermen. Commencing immediate preparations for the battle against the Daleks, the Cyber-Leader ordered an immediate quarantine of the chamber holding the Void sphere as well as emergency upgrades of Torchwood personnel to bolster the Cybermen's numbers, with the Doctor being preserved due to the Cyber-Leader deducing that he held vital information on the Daleks in light of his increased adrenalin.
Addressing the Doctor, the Cyber-Leader voiced its observation that he was proof that emotions were an ultimately destructive flaw. The Doctor agreed, but retorted that he liked hope, calling it a good emotion as he indicated to the Cyber-Leader that it was coming. Indeed, as soon as the Doctor spoke, a force of Preachers led by Jake Simmonds immediately arrived from the parallel Earth, with the Cyber-Leader being too late to realise as the Preachers neutralised his Cyberman cohort. The Cyber-Leader itself sustained a direct hit from an energy blaster fired by Jake. Collapsing to the floor on its knees as its head exploded, the Cyber-Leader was terminated. The Cybermen elsewhere learned that the Cyber-Leader had been destroyed and proceeded to immediately install a new Cyber-Leader, with a volunteer being upgraded. (TV: Doomsday)
Alternative timeline Edit
During the war between the Cybermen and the Preachers in their own universe, the Cyber-Leader was selected by the Cybermen to lead them and replace the Cyber-Controller. The Cyber-Leader coordinated the Cyber battle plans and the Cybermen proceeded to clear all the Preacher bases from the planet. The Cybermen, victorious, viewed the Cyber-Leader as obsolete and deleted it. (GAME: Cyber Assault)