The Cult of Skaro (named after Skaro, the original homeworld of the Daleks) 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
Little is known of the Cult of Skaro. During the Last Great Time War they operated as a final strategic reserve - rather than fighting, they crewed a Void Ship and waited in the space between universes, along with what they called the Genesis Ark, a piece of Time Lord technology. They thus avoided the destruction of the Dalek fleet. (DW: Army of Ghosts / Doomsday, Daleks in Manhattan)
The meddling of the Torchwood Institute began to open the Void. At some point the Void Ship began to materialise in the Torchwood Tower, which had been built around the gap into the Void so that Torchwood 1 could study it. When the Void Ship finally fully materialised, the Cult exited the ship and declared war - or "pest control" - against the Cybermen, thereby leading to the Battle of Canary Wharf. (DW: Doomsday)
After the Battle, the Cult escaped to New York City in 1930, infiltrated the construction of the Empire State Building, and began what they called the Final Experiment - the creation of the Dalek-Humans. (DW: Daleks in Manhattan / Evolution of the Daleks)
- See the individual sections on members for what is known about their respective histories:
Members of the Cult of Skaro
Dalek Sec
Sec was the leader of the Cult of Skaro and the Dalek responsible for the Battle of Canary Wharf in 2007, and was encased in a fearsome black design. He had a high-pitched voice. (DW: Doomsday)
Sec was notable for apparently possessing telepathic abilities in addition to the telekinetic power common to all Daleks. He displayed a capacity for truly radical thought, being the first Dalek to believe that their physical form could be in any way less than perfect, an idea which even other members of the Cult found initially repellent. As a result, he became the first Dalek-Human hybrid as part of the Final Experiment, combining with Mr Diagoras to become independent of his Dalek shell. However, the other Daleks eventually deemed him unworthy of command and exterminated him when he stood in front of the Dalek gunsticks which were poised to shoot at the Doctor. (DW: Daleks in Manhattan / Evolution of the Daleks)
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. He had a high-pitched voice. (DW: Doomsday)
He had four of the plates on the back of his shell replaced with iron as the bonded polycarbide was required for the conductor at the top of the Empire State Building. (DW: Daleks in Manhattan)
He was destroyed by the Dalek-Humans after Gallifreyan DNA was mixed with Dalek and Human DNA in the Final Experiment, causing the Dalek-Humans to question orders. (DW: Evolution of the Daleks)
Caan
A member of the Cult of Skaro, Caan was present at the Battle of Canary Wharf in 2007. He had a low-pitched voice. (DW: Doomsday)
He was the Dalek Mr Diagoras summoned and spoke to when needed in 1930 New York City. (DW: Daleks in Manhattan)
He made himself controller of the Daleks and the Human-Daleks, but when the Human-Daleks rebelled he escaped from them and the Doctor via emergency temporal shift. (DW: Evolution of the Daleks)
Thay
Dalek Thay was a member of the Cult of Skaro and a fearsome enemy. It was Thay that first encounted 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". (DW: Doomsday)
In 1930 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 aid in the construction of the Empire State Building in 1930 New York City. (DW: Daleks in Manhattan)
He was destroyed by the Dalek-Humans after Gallifreyan DNA was mixed with Dalek and Human DNA in the Final Experiment, causing the Dalek-Humans to question orders. (DW: Evolution of the Daleks)