Cult of Skaro

The Cult of Skaro, named after the Dalek homeworld, was a secret group of four Daleks made up of three Dalek drones and one Supreme Dalek.

Purpose
The Cult of Skaro were assigned the task of furthering the Dalek cause through the development of new and unorthodox ideas and strategies. The leader of the Cult claimed that it was created primarily to further the process of Dalek evolution. Their willingness to adopt alien modes of thought was demonstrated by the fact that they had individual names, a concept most Daleks found abhorrent. Led by Sec, the Black Dalek, they answered to no one, not even the Dalek Emperor, although they still revered him. (TV: Doomsday)

Origins
The Cult of Skaro were at first just four ordinary Daleks. Dalek Sec was a commander of a Dalek group sent to wipe out the remnants of the Mechanoids which they succeeded in doing. After doing this all four of them were promoted to become the Cult of Skaro. They were given their names - making them the only Daleks with names - and Dalek Sec was chosen their leader. (DWF: Birth of a Legend)

Survival
They were a secret order who were to think like their enemies in order to destroy them, although their original purpose was to imagine new ways of survival. During the Last Great Time War, they operated as a final strategic reserve - rather than fighting, they escaped into the space between universes, along with what they called the Genesis Ark, a piece of Time Lord technology. Having left the universe, they were not caught in the destruction of the Dalek fleet. (TV: Army of Ghosts / Doomsday, Daleks in Manhattan)

Conflict with the Cybermen
The Torchwood Institute's meddling began to open the barrier to the Void which had been broken down by the Cult's Void ship. Torchwood Tower, known to the public as Canary Wharf, had been built around the gap into the Void so that Torchwood One could study it and use its energy. When the Void Ship opened, the Cult exited the ship and declared war - or "pest control" - against the Cybermen that had invaded Earth from Pete's World, leading to the Battle of Canary Wharf. They then opened the Genesis Ark and released thousands of Daleks onto England. All these Daleks were sucked into the void along with the Cybermen. The Cult survived by using an emergency temporal shift. (TV: Doomsday)

In New York City
The Cult escaped the battle through a temporal shift and ended up in New York City in 1930. They infiltrated the construction of the Empire State Building and began what they called the "Final Experiment" - the creation of a new Dalek race. (TV: Daleks in Manhattan / Evolution of the Daleks) Inside the sewers below the Empire State Building they set up a genetic laboratory and began attempting to create new Dalek embryos. After the failure of this experiment, they tried thinking, as the Cult was designed to, and came up with the idea that they should use Earth's greatest resource, its people. They placed Dalekanium upon the mast of the Empire State Building and devised a plan to fuse the DNA of Daleks and humans using an incoming ray of gamma radiation from the sun. Dalek Sec tested this on Mr. Diagoras and he became a Dalek-human hybrid, now with human thoughts and emotions. Dalek Sec wanted to make the Dalek-humans' DNA 90% human. The other Daleks, although bred to obey Sec, knew it was against the Dalek cause and so changed the DNA to 100% Dalek and imprisoned Dalek Sec. Dalek Sec was later exterminated accidentally after the other Cult members fired their gunsticks at the Tenth Doctor.

The Doctor got in the way of the blast of gamma radiation and so infused the DNA with some of his own. Therefore the humans rebelled and killed Dalek Thay and Dalek Jast. The Doctor offered Dalek Caan—the last surviving Dalek—help but instead of taking it, Caan used an emergency temporal shift to escape (TV: Evolution of the Daleks). Caan returned to the Last Great Time War (despite the fact that the war was time-locked) and rescued Davros from his doomed command ship. Caan, however, went mad from his successful attempt at rescuing Davros. Caan was presumably killed when the Crucible was destroyed, killing the last remaning member of the Cult of Skaro. (TV: The Stolen Earth/Journey's End)


 * See the individual sections on members for what is known about their respective histories:

Dalek Sec
Dalek Sec was at first the Commander of a Dalek force whose mission was to wipe out the Mechanoids. Sec commanded from on the battlefield and overlooking the field from vantage points. After the Mechanoids were exterminated, Sec returned as ordered to the Emperor. There, Sec was selected as the leader of the Cult and given his name. He was then sent to the weapons research area for upgrades where he was newly-housed in Metalert Dalekanium that was more defensive than the average Dalekanium. Sec, along with the rest of the Cult, then went on to begin using their initiative to defeat enemies. (DWF: Birth of a Legend)

Dalek Sec was responsible for the Battle of Canary Wharf in 2007. He was designated by his black casing. Sec ordered an escape via an emergency temporal shift to avoid being pulled into The Void. (TV: Doomsday)

Sec was notable for displaying a capacity for truly radical thought. He became the first Dalek to believe that their physical form could be in any way less than perfect, an idea which even the other members of the Cult found initially repellent. As a result, he became the first human-Dalek hybrid as part of the "Final Experiment", combining with Mr. Diagoras, using his flesh to become independent of the Dalek shell. However, the other Daleks eventually relieved him of his command, no longer considering him to be a Dalek. He was exterminated by Dalek Thay after taking a shot meant for the Tenth Doctor. (TV: Daleks in Manhattan / Evolution of the Daleks)

Dalek Caan
Former Attack Squad Leader of the 30th Dalek Assault Squad, Dalek Caan was present at the Battle of Canary Wharf in 2007 and was possibly the second-in-command after Sec. He had the lowest-pitched voice out of the members of the Cult. (TV: Doomsday)

He was the Dalek Mr Diagoras summoned and spoke to when needed in 1930 New York City and served as the Cult's link to the outside world. (TV: Daleks in Manhattan)

After Sec became a human-Dalek, Caan and the other Cult members no longer considered him to be a Dalek and turned against him. Caan made himself Controller and became linked to the Dalek-human army, but when the Dalek-humans rebelled and destroyed Jast and Thay, he destroyed them in turn. Now being the last surviving Dalek in the universe, the Doctor confronted Caan but the Dalek escaped from him via an emergency temporal shift. (TV: Evolution of the Daleks)

After teleporting away from the Doctor, Dalek Caan found himself in the first years of the Last Great Time War. He interfered with the timeline and eventually saved Davros from his death, despite the war's events being time locked. Although Caan was almost destroyed in the process, it allowed him to see the whole of time and space. He was thus able to foresee events, but only at the cost of his sanity. The top half of his casing was destroyed, presumably during these events as well. After this, he was presumed to serve Davros - and later the Dalek Supreme - during their creation of the Reality bomb. However, since he had seen all of time and space, he saw the true nature of the Daleks. Dalek Caan betrayed them, withholding the fact that they would be stopped by the Doctor. He said that he had seen the true nature of the Daleks and disliked it. He was presumably killed in the destruction of the Crucible. (TV: The Stolen Earth / Journey's End)

Dalek Jast
Dalek Jast was a member of the Cult of Skaro and a participant in the Battle of Canary Wharf in 2007. Jast was the first to realise that the Doctor was still alive after the arrival of the Cybermen when he noticed the Doctor on a video transmission with the Cyber-Leader. He had the highest-pitched voice out of the members of the Cult. (TV: Doomsday)

Like Daleks Caan and Thay, Jast was created to follow Sec, but began to have doubts about his leader when Sec became the first human-Dalek. Along with Caan and Thay, Jast later turned against Sec. When the Dalek-humans questioned their orders after the Tenth Doctor's Gallifreyan DNA was mixed with theirs, the new Daleks battled Jast and Thay, resulting in Jast's destruction. (TV: Evolution of the Daleks)

Dalek Thay
Former Commandant of Station Alpha, Dalek Thay was a member of the Cult of Skaro and was the first Dalek to encounter the Cybermen during the Battle of Canary Wharf in 2007. Thay was tricked into identifying himself by the Cybermen after both sides refused to "identify first." Thay spoke in a low-pitched voice with a slight nasal croak.(TV: Doomsday)

In 1930 in New York City, Thay originally had strong feelings against the Final Experiment, claiming that it was against the Dalek ideology of racial purity, but eventually conceded that it was necessary for survival. To complete the Empire State Building before the gamma strike would hit Earth, three of the back plates of Thay's casing were removed and attached to the building's mast, being replaced with iron as the bonded polycarbide of the plates was required to attract the gamma strike. (TV: Daleks in Manhattan)

The Dalek-humans, after Gallifreyan DNA was mixed with their Dalek and human DNA in the "Final Experiment", questioned orders and revolted against their Dalek masters, destroying Thay and Jast. During the events leading up to that, Thay was the one who killed Dalek Sec, firing a blast at the Doctor that Dalek Sec took to save the Doctor. (TV: Evolution of the Daleks)

Behind the scenes

 * Throughout their appearances, Thay, Jast and Caan's recognition codes switch.
 * In TV: Doomsday, Dalek Jast's recognition code had two short lines on the bottom and middle and a long line on the top, and Dalek Caan's had two short lines on the top and bottom, and a long line on the middle; while in TV: Daleks in Manhattan and Evolution of the Daleks, Jast's recognition code had two short lines on the top and bottom and no third line in the middle, and Caan's recognition code had two short lines on the middle and bottom and a long line on the top.