Voord

The Voord (also sometimes referred to as the Voords) were a race of semi-aquatic beings that tried to conquer many ocean planets, including Marinus, Kandalinga and Hydra.

Biology
The Voord usually wore a complete black bodysuit, which was similar to a frogman's wetsuit and flippers. This suit tended to be effective protection from hostile elements. It was not, however, completely impermeable. Barbara once discovered an empty Voord suit with two puncture marks, suggesting that the acid had consumed the Voord within. The Voord were also armed with commando-style knives.

Still, the shape of the suit suggested a few things about basic Voord anatomy. They were, for example, humanoid. And they had three appendages on their heads — a thin stick with a circle at the front and two loop-like horns on the side. Nevertheless, not all Voord had these cranial appendages. Yartek, the leader of the Voord on Marinus, only had two appendages, one on the right and left of his head. (TV: The Keys of Marinus)

Using these, the Voord were capable of telepathically communicating with each other. The leader had the higher intelligence and was able to control others with this organ. They could also control the minds of the Fishmen, but they could not read the First Doctor's mind. If this organ was damaged or removed, the Voord would be rendered senseless. (PROSE: The Fishmen of Kandalinga)

The Voord mask fused with the wearer and usually could not be removed without killing them. The mask gave the Voord their telepathic abilities. Native Voord were given their masks in a ceremony when they achieved maturity. (AUDIO: Domain of the Voord)

On planets they conquered, the Voord converted the natives into Voord creatures by fusing them with Voord masks and suits — the mask tested their loyalty to the Voord, and if they were found disloyal, they were killed. While indistinguishable from the outside, unlike the native Voord of the Blood Tree, the converted Voord creatures had much less autonomy, and were mostly puppets of the native Voord commanders. The Voord suits lengthened their lifespans to a thousand years. (AUDIO: Domain of the Voord)

Technology
On Marinus, the Voord used one-man submarines, (TV: "The Sea of Death") while on Kandalinga the Voord used large barges to travel around on. The barges travelled above the surface of the water and were capable of stopping and speeding up quickly. The barges made no sounds and no waste-products and the First Doctor believed them powered by anti-gravity. (PROSE: The Fishmen of Kandalinga)

History
A Voord expedition led by Yartek invaded the planet of Marinus. The Voord found a way to relieve themselves from the control of the Conscience of Marinus. They sought to take control of the Conscience, thus taking control of Marinus. They travelled to the island of the Conscience and killed the Keeper. When the First Doctor and his companions returned with the Conscience's keys, Ian Chesterton stopped them by handing Yartek a fake key, which destroyed the Conscience and killed Yartek. (TV: The Keys of Marinus)

A few hundred survivors were able to escape, take two of the keys of Marinus, and make their way to Kandalinga. As there was no land to build on, they were forced to rebuild their ship into a base and enslaved the Fishmen as workers. They planned to convert the oceans to land and build ships to return to Marinus, a plan that would take thousands of years to complete. (PROSE: The Fishmen of Kandalinga)

A hundred years after Yartek's defeat on Marinus, the Doctor encountered another group of the Voord, led by Overlord Tarlak and Commander Nebrin on the planet Hydra. (AUDIO: Domain of the Voord)

Many thousands of years later, the First Doctor came into contact again with the Voord on Kandalinga. After the Doctor was brought to the leader, the leader believed that the Doctor's ship could be used by the Voord. The Doctor was able to stop the leader, breaking his telepathic control and allowing the Fishmen to rise up and take back their planet. (PROSE: The Fishmen of Kandalinga)

On Marinus, the Daleks and Voord were fighting one another when the Daleks learnt that the Voord knew of a mushroom, known as the Great Power, that granted superhuman abilities. The Daleks pretended to form an alliance with the Voord. Discovering the First Doctor, they forced him to hand over the secret of ultkron travel. On board the spaceship headed to Earth, the Doctor told the Voord about the Daleks' plan to destroy them. The Voord attempted to round up the Daleks, but one Dalek escaped and freed the other Daleks. A fight broke out between the two species. A Dalek raygun hit the ship's power centre, disintegrating the ship. The Daleks evacuated on their hoverbouts, while the Doctor and the lone Voord survivor, the Chief Voord, got away in an escape capsule, which landed in a South American jungle. (PROSE: Doctor Who and the Daleks)

One account suggested that the Voord on Marinus began experimenting with a Worldshaper, which accelerated time locally and "quick-evolved" the Voord. Over time they replaced their body parts with cybernetic parts. The Sixth Doctor, Frobisher, Peri Brown and Jamie McCrimmon attempted to stop the Voord. Jamie sacrificed himself to destroy the Worldshaper, which caused a blast that accelerated time. Marinus became known as Mondas and the Voord evolved into entirely cybernetic creatures called Cybermen. (COMIC: The World Shapers) Due to the paradoxes and shifts in causation caused by the Last Great Time War, the Voord felt that their biology had benefitted from the War. The Voord sided with the Time Lords and mounted resistance against the Daleks. Siatak pleaded with the War Doctor after the Daleks attacked Marinus to speak to the Time Lords on their behalf about the future of their species.

Sometime later, the group orchestrated a meeting of the Tenth, Eleventh, and Twelfth Doctors on the planet. The detonation of a Continuity Bomb forced the three Doctors and their companions to flee through various alternate timelines, eventually encountering a timeline where the Twelfth Doctor had left the universe after he was 'betrayed' by Clara Oswald to become the new leader of the Voord, who had removed themselves from the universe before the end of the Time War; this whole scheme had been set up so that he could stop his past selves from finding Gallifrey, with the final goal of ensuring his own existence so that he could bring the Voord back into the universe to become the new Time Lords. (COMIC: Four Doctors)

Undated events
The Seventh Doctor and Ace encountered the Voord during their travels. (PROSE: Prime Time)

Professor Thripsted believed that the Voord were the direct ancestors of the Remote, and their entire planet a sociology experiment conducted by Faction Paradox (as outlined in Genetic Politics Beyond the Third Zone). (PROSE: Interference - Book Two)

A Voord was a slave in the Frenko Bazaar, and joined the uprising led by the Ice Warrior, Araxus. (COMIC: Prisoners of Time)

Other references

 * The misguided renegade Time Lord known as the Monk was, at one time, a technical advisor to the Voord. (PROSE: No Future)
 * When a museum was made from the Tenth Doctor's memories in the Matrix, it contained a Voord helmet. (COMIC: The Forgotten)
 * Iris Wildthyme was said to have fought Voord in the Death Zone. (PROSE: Verdigris)
 * Homunculette claimed that even the Voord were more frightening than the Krotons. (PROSE: Alien Bodies)
 * The Eighth Doctor jokingly speculated that the Enemy might be "Yartek, leader of the alien Voord, carrying a big stick." (PROSE: The Taking of Planet 5)

Behind the scenes

 * The Voord were originally scripted as "eel-like". (REF: Doctor Who Monsters: A Bestiary)
 * The Voord headpieces were individually crafted for each actor. (REF: Doctor Who Monsters: A Bestiary)
 * Based entirely upon the their televised appearance, it would be possible to believe that the Voord were not necessarily a species at all, but merely a cultural grouping of Arbitans. Arbitan tells Ian Chesterton, "The man who just attacked me was a Voord." Later, he also describes Yartek as "a man named Yartek". Philip Hinchcliffe's novelisation seeks to make things clearer, by changing the language to, "The creature who attacked me was a Voord," and by referring to Yartek as a "Voord named Yartek".