CyberIsomorph

CyberIsomorph, or simply Isomorph, was the term assigned by the ArcHivist Hegelia to a Cyberman subspecies, a variant of CyberNeomorph that was stranded in the late 20th century. (AUDIO: The Ultimate Cybermen)

Appearance
Following on from original CyberNeomorphs, Hegelia observed that the Isomorph Cybermen had undergone a subtle design change; their helmet and chest pieces were of shinier, more reflective material. At the lower leg and forearm was fixed a loose band of transparent piping whose function was uncertain. (AUDIO: The Ultimate Cybermen, TV: Silver Nemesis)

Vulnerabilities
The Isomorphs inherited both the resilence and weaknesses of the earlier Neomorphs and the preceding Cyberman subspecies. While 20th century human firearms inflicted little to no damage upon them, the Cybermen remained vulnerable to gold. Indeed, Lady Peinforte and Ace, using a bow with gold-tipped arrows and a slingshot with gold coins respectively, were able to destroy these Cybermen with a single hit to their chest panels. However, the Cyber-Leader proved more resilient as it survived being struck by a coin, which it dislodged from its chest unit, only to be finally killed when Richard Maynarde thrust an arrow into its chest. (TV: Silver Nemesis)

Hierarchy
Like the original Neomorphs, the Isomorphs were led by a Cyber-Leader, distinguished by their black side handles, who was assisted by a Cyber-Lieutenant. (TV: Silver Nemesis)

Weaponry
Hegelia observed that the CyberIsomorphs carried heavy Cyber-guns of a design not unrelated to those used by early CyberFaction. (AUDIO: The Ultimate Cybermen, TV: Silver Nemesis)

Spacecraft
In 1988, the CyberIsomorphs operated a Cyber-Fleet which appeared to consist of thousands of Cyber-Warships. (TV: Silver Nemesis) However, Hegelia suggested that this was a deception, and that the CyberIsomorphs' fleet consisted of no more than three Cyber-ships. (AUDIO: The Ultimate Cybermen)

Origin
In an attempt to avert their future defeat, CyberNeomorphs based on Telos used a stolen time vessel to travel back centuries in the past to Earth in 1985, where they intended to destroy the planet in order to prevent the destruction of their original homeworld, Mondas, which occurred in the following year. Ultimately, this plot was foiled by the Sixth Doctor. (TV: Attack of the Cybermen) However, a group of Neomorphs remained stranded in the late 20th century. (AUDIO: The Ultimate Cybermen)

Operations
In November 1988, a scouting party of Cybermen was sent to Earth in search of a statue made of validium called Nemesis, a Time Lord weapon. The Cybermen met Lady Peinforte, who brought many of their number down with gold-tipped arrows. The Leader apparently forced the Seventh Doctor to surrender the Nemesis. Their force was destroyed by Nemesis as the Doctor had instructed. (TV: Silver Nemesis)

Legacy
UNIT collected the body of one of the Cybermen that were killed by Lady Peinforte and stored it at the Underbase. (COMIC: The Age of Ice)

Alternate timeline
In an alternate timeline where the Cybermen at the end of the universe allied with Rassilon to take over history, a Nomad Cyber-Leader commanded at least one CyberIsomorph on Skaro, where the Cybermen had erased the Daleks from history. When the Fifth Doctor and Peri Brown arrived on the planet, the Cyber-Leader identified the Doctor and ordered one CyberIsomorph to kill him. Elsewhere, the Seventh Doctor was planting Nemesis mines on an Isomorph Cyber-Fleet when he was found and attacked by a cyber-converted Ace. Ultimately, this timeline was negated when the Twelfth Doctor and Rassilon regenerated the universe. (COMIC: Prologue: The Fifth Doctor, Prologue: The Seventh Doctor, Supremacy of the Cybermen)

Behind the scenes
"Isomorph" was coined by Cyber-Leader actor David Banks to distinguish the Cybermen seen in Silver Nemesis, who sported several minor cosmetic differences from the earlier "Neomorphs", as well as explaining why that story had them present in the 20th century, linking to the Neomorphs' earlier use of time travel in Attack of the Cybermen.

Before Silver Nemesis introduced the Isomorphs, FASA's The Doctor Who Role Playing Game featured a "Model VII Cyberman", said to be all but identical to the "Model VI" Neomorphs, in Countdown''.

Doctor Who: Cybermen claims that the Cybermen seen in Silver Nemesis were in fact late CyberNomads who used time travel to invade Earth in 1988, separate from the Neomorphs.