Cult of Skaro

At last. The Cult of Skaro. I thought you were just a legend.The Doctor.

The Cult of Skaro, named for the Dalek homeworld, was a secret group of four Daleks—three Standard Daleks and one Black Dalek—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.(DW: Doomsday)

History

A secret order. Above and beyond the Emperor himself. Their job was to imagine. Think as the enemy thinks. Even dared to have names. All to find new ways of killing.The Doctor.

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 ordered by the Dalek Emperor to return to him. They arrived and were promoted to become the Cult of Skaro. They were then given their names and Dalek Sec was elected as their leader. (DWF: Birth of a Legend)

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 avoided being caught up in the destruction of the Dalek fleet.(DW: Army of Ghosts / Doomsday, Daleks in Manhattan)

The Torchwood Institute's meddling began to open the barrier to the Void which had been broke 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 1 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, thereby leading to the Battle of Canary Wharf.(DW: Doomsday)

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.(DW: 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 took a shot at the The Doctor.

As the gamma radiation came in the Doctor got in the way of the blast and so confused the DNA with some of a Time Lord's. Therefore the Dalek-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 teleport out. He then teleported into the Time War on Davros's command ship taking them to Earth, but at the cost of his sanity and losing his metal head.

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

Members of the Cult of Skaro

Dalek Sec

If you choose death and destruction, then death and destruction will choose you.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. (DW: 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 Doctor. (DW: Daleks in Manhattan / Evolution of the Daleks)

Dalek Caan

I will be the destroyer of our greatest enemy!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 fourth-in-command but after Sec was promoted to leader due to his pushiness and ruthlessness instead of second in command,Dalek Thay. He had the lowest-pitched voice out of the members of the Cult. (DW: 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. (DW: 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. (DW: Evolution of the Daleks).

After teleporting away from the Doctor, Dalek Caan found himself in the first years of the Time War. He interfered with the timeline and saved Davros from his death, despite the war's events being time locked. Caan was almost destroyed in the process, and saw the whole of time and space, which allowed him to foresee events, but caused his insanity. It is assumed that the top half of his casing was destroyed during these events, as well. He presumably then served Davros and then the red 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, and betrayed them, withholding the fact that they would be stopped by the Doctor. He was presumably killed in the destruction of the Crucible. (DW: The Stolen Earth / Journey's End)

Dalek Jast

Now we will destroy our greatest enemy - the Doctor!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.(DW: Doomsday)

Like Caan and Thay, he was created to follow Sec but had doubts about his leader when Sec became the first Human-Dalek. Along with Caan and Thay, Jast turned against Sec. When the Dalek-Humans questioned their orders after Gallifreyan DNA was mixed with theirs, the new Daleks battled Jast and Thay, resulting in Jast's destruction. (DW: Evolution of the Daleks)

Dalek Thay

You will die, Doctor. At the beginning of a new age.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.(DW: 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. (DW: 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. (DW: Evolution of the Daleks).