Cyber-Earth

In an alternate timeline, Cyber-Earth was the designation for a version of the planet Earth which had been upgraded by the Cybermen in the year 2006. (COMIC: Supremacy of the Cybermen)

Origin
At the end of the universe, after being banished from Gallifrey by the Twelfth Doctor, Lord President Rassilon found the surviving Cybermen. Returning to Gallifrey with them, Rassilon seized control of the planet, using the Time Lords' resources to launch an invasion of the universe across time and space. To distract the Doctor, the Cybermen launched attacks at various points in his time stream.

Alternate Timeline
As a result of one of these incursions, Earth had been colonised by the Cybermen within a period of three days in the year 2006. Seizing the TARDIS from the Ninth Doctor and his companions, Rose Tyler and Jack Harkness, the Cybermen proceeded to convert humans into Cyber-Warriors. In London, Jackie Tyler was pursued by a converted dog through the Powell Estate, which had been reduced to ruins by the attack. Using a shielded flyer, the Doctor and his companions rescued Jackie before breaking into the Cybermen's base. Finding the TARDIS, the four entered the control room just before the control console exploded as TARDIS approached the point of implosion, generating a containment field to protect the Earth.

Exiting the TARDIS, Jack used his spare gun to hold off the Cybermen as the group made their way back to the flyer, only to be shot dead by Rose, who began to undergo cybernisation having been exposed to an airborne techno-virus. Immediately after, the Doctor found that nanites were beginning to convert him, starting with his right hand, before reaching the safety of the flyer, which protected Jackie from the virus. However, as the Doctor's cybernisation had already started, he was rejected by the flyer's shield. Returning to the TARDIS, the Doctor deactivated the containment field, intending for the Heart of the TARDIS to tear apart and take the Cyber-Earth with it. Despite being instructed to stay within the flyer's shield, Jackie joined the Doctor in the TARDIS. At that point, the Doctor found that the TARDIS built-up energy had been siphoned away, preventing it from imploding. By them, the converted Rose had entered the TARDIS and advanced on the Doctor and Jackie, intent on "deleting" them.

Recollection
On Gallifrey, the Twelfth Doctor gained new memories of the Cyberman attack experienced by the Ninth Doctor, amongst other incarnations. By that point, Rassilon had been betrayed by the Cybermen, who intended to use the regeneration energy of all Time Lords to regenerate the universe in their own image. However, by enlisting Rassilon's aid, the Twelfth Doctor was able to regenerate the universe in order to remove the Cybermen's alterations, destroying the Cybermen on Gallifrey. In the restored timeline, the Doctor retained his knowledge of the alternate timeline and hoped that Rassilon, now an exile again, did so as well. (COMIC: Supremacy of the Cybermen)