Dalek Jast

Dalek Jast was a member of the Cult of Skaro. He had the highest-pitched voice of the members of the Cult.

Origins
Jast was a bronze Dalek and the Force Leader of the Outer Rim Defensive Battalion and was chosen to be part of the Cult of Skaro along with Dalek Thay, Dalek Caan and their leader, Dalek Sec. The purpose of the cult was to "think like the enemy" and come up with novel and unorthodox methods of furthering the Daleks' cause in a predicted war that was coming. It was their leader, Dalek Sec, who began using their initiative to defeat enemies. (PROSE: Birth of a Legend) During the Last Great Time War the cult escaped the carnage by hiding between realities in a Void ship, along with the Genesis Ark, which contained an army of imprisoned Daleks. (TV: Doomsday)

The Battle of Canary Wharf
The Void ship appeared in Torchwood One in 2007. The Cult emerged after an army of five million Cybermen appeared across the world. (TV: Army of Ghosts) Jast was the first to realise the Tenth Doctor was still alive after the arrival of the Cybermen when he noticed the Doctor on a video transmission with the Cyber-Leader. In the sphere chamber, Jast activated the awakening process and monitored the Genesis Ark on its priming consoles until the final stage of the awakening; time travellers used their hand to transmit the universe's background radiation as power supply. During the battle, the Genesis Ark rose and unleashed millions of Daleks on the world. Shortly after, the Doctor and Rose sucked the Daleks and Cybermen back into the void. (TV: Doomsday) The Cult of Skaro used an Emergency Temporal Shift to escape to 1930 New York City. (TV: Daleks in Manhattan)

The Final Experiment
Like Caan and Thay, he had doubts about his leader's choices on preserving the Daleks. Thay protested to Sec about him becoming the first human-Dalek, Jast backed Thay's objections, saying Daleks were supreme and humans were weak. Nonetheless, he assisted, injecting Sec with Chromatin solution. Along with Caan and Thay, Jast turned against Sec during the creation of the Dalek-humans. When the Doctor discovered the group had overridden the gene feed, Jast took aim at him, ordering him to step away from the controls. Sec ordered Jast to stand down, to be told, "He is an enemy of the Daleks, and so are YOU!" After the Doctor escaped to prevent the Gamma strike, Sec protested that the others had betrayed him. Jast replied that it was Sec who had told them to imagine, resulting in them imagining their leader's irrelevance. At the Laurenzi theatre, Jast and Thay confronted the Doctor with the imprisoned Dalek Sec. Thay announced it was the beginning of a new age. Jast added Earth would become the new Skaro. When the Dalek-humans questioned their orders after Gallifreyan DNA was mixed with theirs, Thay fired on the new Daleks. Jast instantly supported Thay in the battle. When Thay was destroyed, all the new Daleks concentrated on Jast, resulting in his destruction soon after. (TV: Evolution of the Daleks)

Personality
He had the highest-pitched voice of the members of the Cult. Jast was highly reserved, only speaking when addressed or when he believed it to be vital to the matter at hand. He was the most faithful servant to Dalek Sec and often stayed at his side during their time at the Empire State Building in 1930, and was the last to join the cult's rebellion against Sec. (TV: Evolution of the Daleks)

Other information
Dalek Jast, as with all Daleks that originated from the Last Great Time War, possessed markings below his eyepiece to identify him. (TV: Doomsday) Some reports of the Battle of Canary Wharf mentioned "Dalek Rabe", but these reports were regarded as errors, (PROSE: The Secret Lives of Monsters) given that only Sec, Jast, Caan, and Thay were part of the Cult of Skaro. (TV: Doomsday)

Prop
Dalek Jast was depicted using a bronze Dalek prop originally created for Bad Wolf/The Parting of the Ways.

Other matters

 * The original shooting script identified Dalek Jast as Dalek Rabe. The Doctor Who Files and Doctor Who: Battles in Time identify him as such.
 * Dalek Jast is notably the least talkative of the Cult of Skaro. In David Tennant's video diary for Evolution of the Daleks, Nicholas Briggs, voice actor for the Daleks, revealed that he had made a request to executive producer Russell T Davies for Jast's dialogue to be minimised because he had chosen to portray him with a "ridiculous"-sounding voice, which made it hard to take Jast seriously if he spoke too copiously.
 * Jast, along with Thay and Caan, is erroneously depicted as a black-domed Dalek on the "Cult of Skaro" card from Doctor Who: Battles in Time.