The Cybermen of the parallel world, nicknamed "Pete's World" were created and designed by dying buisness tycoon John Lumic who was incharge of Cybus industries.
Lumic wished to create the next level of mankind so humans could live forever. Lumic would remove all human emotions making them stronger, and the human brain would be placed into a disease free almost indestructible cybernetic body. The brain soaked with chemicals and all emotions removed would make them powerful.
Lumic called this the ultimate upgrade. The new Cybermen seemed to be heavier and stronger than the Mondas Cybermen.
However, the President of Great Britain refused to allow people to be upgraded. Although Lumic went ahead with his plan by kidnapping homeless people and upgrading them into Cybermen.
Using the EarPods he designed and sold out to most of the population of Great Britain, Lumic took mental control of the people of London, marching thousands to be cyber-converted. After his life-support systems were damaged by his assistant, Mr. Crane, Lumic was converted into the Cyber-Controller. However, the Tenth Doctor and his companions, having accidentally landed on the parallel Earth, managed to foil his plans. They freed London from mental control and disabled the Cybermen's emotional inhibitors, causing them to go insane and in some cases explode. Lumic himself fell to his apparent death into the burning remains of his factory. A human resistance group, the Preachers, then set about to clean up the remainder of Lumic's factories around the world.
The Preachers first made an attack on Paris, France. Where another Cyber Factory was located and battled the Cybermen. Mickey Smith used the captured Cyber zeppelin to fight the Cybermen and helped defeat them.
Cybermen on other countries were sealed inside their factories, and a debate went on discussing what should be done with them. Then suddenly the Cybermen, which numbered in five million simply vanished. They had crossed the void which was between worlds, and entered the real world, the Doctor's universe.
At first they appeared like ghosts which the people of Earth thought was their dead loved ones, they established a base inside the Torchwood Tower at Canary Wharf. While there, they started making new Cybermen, using what materials they could find. After two months (three years in parallel Earth time), the Cybermen suddenly appeared in their true form, occupying every landmass on the planet before breaking into houses and promising to upgrade all humans, commanded by the new Cyber-Leader.
They told the Doctor that they crossed between worlds, by following a void ship which broke down the barriers between universes. The void ship they followed was revealed to be of Dalek origins and four Daleks known as the Cult of Skaro emerged from the ship along with the genuses ark.
When Dalek Thay of the cult encountered two Cybermen, the Cybermen at first thought they should join each other and upgrade the universe and Dalek Thay declined the request. The two Cybermen tried to delete Thay, but the Dalek simply exterminated them.
The Cyber Leader delcared war upon the Daleks, although the Cult's leader Dalek Sec saw the Cybermen as weak. After a skirmish between humans, Cybermen and Daleks, the Cult travelled to the main room in Torchwood's Canary Wharf, elevated outside above the roof, and opened the Genesis Ark, releasing millions of Daleks who, under Sec's command, started to "exterminate all life-forms below", killing human and Cyberman alike.
The Cybermen's laser weapons and special guns could not kill the Daleks, while one shot from a Dalek's gunstick could kill a Cybermen instantly.
The Cyber leader realized that too many Cybermen were being destroyed by the Daleks, and ordered other Cybermen in London to go to Torchwood and fight the Daleks, although many would be destroyed. Towards the end of the Cybermen-Dalek battle, the Cybermen, desperate for more troops, began directly converting people rather than transplanting their brains into Cybershells. One victim of this process was Lisa Hallett, girlfriend of Ianto Jones.
The Tenth Doctor and Rose Tyler opened the Void and anything contaminated with void stuff was pulled in. This included the Cybermen. Although Dalek Sec and the rest of the Cult escaped with Emergency Temporal shift.
Several of these Cybermen escape the void into 1851 Christmas eve, led by a Cyber-Lord and Miss Mercy Hartigan, however they were heavily damaged and had lost a lot of memory so they were using infostamps to regain their memory, without having the sufficient needs to fully upgrade humans so they had to make do with upgrading cats and dogs into Cybershades. Using kidnapped children they planned to build a Cyberking to help them take over the Earth not long before the finishing of the robot the cybermen decide to convert Mercy into their new leader, however the Doctor tried to strike a peace bargain with them saying he would take Mercy and the Cybermen to a planet were they can live in peace, they refuse however and the Doctor severs her connections and she screams in horror as to what she has become, before the broken connection destroys her and the Cybermen, the Doctor then traps the Cyberking in the void.
A while later the Cyberleader and the Cybermen join the Pandorica Alliance in an attempt to trap the Eleventh Doctor in the Pandorica.