This Cyber Leader took command of the force of five million Cybermen of a parallel Earth, which had crossed from their parallel Earth to the Earth of the Doctor's universe, in the Battle of Canary Wharf following the destruction of the first Cyber-Leader.
This Cyberman was a member of the contingent which had invaded the Torchwood Tower. When the Cybermen faced a violent confrontation with the Cult of Skaro, it was among the Cybermen which oversaw the emergency upgrading of Torchwood personnel to bolster their numbers against the Daleks. Learning that Cyber-Leader One had been terminated, having been destroyed at the hands of the Preachers, it volunteered to be upgraded into Cyber-Leader.
As the Cult of Skaro advanced into Torchwood's artefact room, the Cybermen formed a momentary truce with the Preachers and soldiers of Torchwood in order to oppose the quartet of Daleks, who despite being immensely outnumbered proved impervious to any assault. With many Cybermen being exterminated, the Cyber-Leader sent an emergency command to all Cybermen units to converge on the Torchwood Tower. The situation took a turn for the worst when the Cult of Skaro escaped from the Torchwood Tower and unleashed a force of millions of Daleks which had been imprisoned within the dimensionally transcendental Genesis Ark, proceeding to exterminate humans and Cybermen alike in Canary Wharf and beyond.
As a last resort, the Cyber-Leader took his cohort to retreat through the dimensional breach at the top floor of the tower in order to "regain the homeworld". However, the fleeing Cybermen found their path blocked by a single Cyber Unit, converted from Torchwood director Yvonne Hartman, who told them that they would not pass. The Cyber-Leader ordered the Cyberman to explain its meaning, only for the converted Hartman to repeat her statement as she opened fire on the oncoming Cybermen with an energy blaster, terminating the Leader just before the Tenth Doctor and Rose Tyler opened the breach, resulting in the millions of Cybermen and Daleks which had been soaked in Void stuff being sucked into the 'hell' of the Void. (TV: Doomsday)