Cybermen are cyborgs from Earth's twin planet, Mondas.
In Worlds in TimeEdit
Cybermen have been seen in advertisements for Doctor Who:Worlds in Time, but none have yet been encountered within the game. Cybermen Shards are sometimes offered as rewards for missions. It is presumed that they will appear in The Library or Alfava Metraxis. They are one of the many villains to fight in the new Challenge Mode (2nd April, 2013). In the first Earth Challenge Mode, your mission is to stop the Cybermen from disrupting Earth's history.
In Doctor WhoEdit
Cybermen first appeared in the episode The Tenth Planet (1966). The Mondasian scientists and doctors realised that their race was dying out (as a result of the planet drifting out of the solar system), and became desperate to survive. In an attempt to survive, they removed all "weak" and "unnecessary" body parts, leaving only brain; the brain was placed inside a cybernetic body made of plastic and steel, and an emotional inhibitor was installed. This mechanism conditioned the brain, so that the resulting Cybermen could not feel any physical pain, had no emotions, no individuality and no personality. They are uniform, emotionless and without humanity. Cybermen believe emotions are a weakness, and their ultimate goal is to survive. Their primary method of doing this is increasing their numbers through converting humans (who are virtually identical to the former Mondasians). Cybermen have also converted dog-like animals into Cybershades; black, furry creatures with a bronze helmet and hands that possess acrobatic skills, and rodent-like creatures into Cybermats; small, "metal rats" that can be used to convert people into Cybermen/Cyberslaves or pick up/carry energy.
In a parallel world, the Cybermen were created on Earth by John Lumic, who used his company Cybus Industries in an attempt to "upgrade" humanity. This version of the Cybermen also landed in Victorian London, where they enslaved children to build a Cyberking: a dreadnought class ship with no obvious intelligence of it's own; it merely holds the image of a Cyberman.
A Cyber-centurion was found in pieces and guarding the Pandorica. It had "had a run-in with the locals".
Cybermen were discovered waiting in a crashed Cybership under Colchester, UK. They were damaged and relied on energy picked up by Cybermats.