Scientist Dalek (The Guide to the Dark Times)

A Dalek Scientist was a member of the Dalek Time Squad, a battalion of Time-Sensitive Daleks deployed by the Emperor of the Restoration to investigate numerous divergences in time and manipulate them for the benefit of the Restoration Empire. (PROSE: The Guide to the Dark Times) The divergences investigated by the Dalek Scientist and the Dalek Time Squad had been caused by the Tenth Doctor's attempt to render the Kotturuh extinct during the Kotturuh crisis in the Dark Times. (PROSE: The Knight, The Fool and The Dead)

Physical appearance
The Dalek Scientist's casing resembled those of the silver Daleks of the Restoration Empire, but with a crimson dome, sense globes and slats. Its eyestalk lens was a bluish white with small green, yellow and blue lights surrounding it, while its luminosity dischargers were somewhat yellow. Instead of the familiar plunger-like structure, its manipulator arm ended in a six-fingered "claw". (PROSE: The Guide to the Dark Times)

Biography
After the Dalek Time Squad captured the Eighth Doctor, (AUDIO: He Kills Me, He Kills Me Not) the Dalek Scientist travelled with the Doctor, the Dalek Time Commander and the Dalek Prime Strategist to Wrax. Whilst the Doctor and the Prime Strategist went to examine the Wraxians' gallery, the Time Commander, the Executioner and the Scientist met the President of Wrax, offering an alliance and asking for a demonstration of the Wraxian superweapon, the Devolver. She agreed, but betrayed the Daleks and trapped the three Daleks, having acquired the Dalek origin matrix from a dead transmat pilot and intended to use the Devolver against the entire Dalek race. The three Daleks escaped, but the Strategist persuaded them to let the Doctor negotiate with the President. The Doctor made an agreement for the Daleks to withdraw in return for the Devolver's dismantling, with the Scientist returning to the Squad's time ship. After the Doctor connected his TARDIS to their saucer's engines, the Daleks travelled back to the Dark Times to find the source of the alterations. (AUDIO: The Enemy of My Enemy)

After the Battle of Mordeela, the Scientist extracted and weaponised the unique lifeforms of the Dark Times as part of the Time Squad's back-up plan as they believed they had failed to correct the timeline. The Commander observed the Scientist working on a Fellonian, which were extinct in the Daleks' time period. (PROSE: Mission to the Known) Under the supervision of the Strategist, the Scientist continued experiments with the aim of creating a more biologically efficient form of Dalek, the Symbiont. They targeted Vampires for the experiments, with the Time Squad eventually capturing a Great Vampire. The Scientist and Strategist extracted its DNA and infused it into a Dalek mutant, creating an undead form of Dalek.

After the Eighth Doctor forced the Dalek saucer into the Time Vortex by detonating an explosive in the engine room, (PROSE: All Flesh is Grass) the Strategist worked with the Scientist to stabilise the vessel. The Scientist diverted power, awakening alien prisoners in cryogenic suspension. The Doctor infiltrated its laboratory and sabotaged the artificial gravity. He teased information out of the helpless Scientist and secretly planted an improvised explosive on it. After escaping to the other side of the saucer the Doctor detonated the explosive, killing the Scientist. (AUDIO: Mutually Assured Destruction)

Psychological profile
River Song described the Dalek Scientist as "a whizz with temporal science". It was not only time-sensitive, but had a strong sense of how actions could affect both the future and the past, allowing it to use "time itself" as a weapon when devising "new and unusual plans" in conjunction with the Dalek Prime Strategist. (PROSE: The Guide to the Dark Times)

Behind the scene

 * Speaking of his portrayal as the Scientist, Nicholas Briggs described him as "very very picky and pedantic".