Berserker Dalek

Berserker Daleks were a new breed of Dalek fielded in the Last Great Time War. They were deployed on simpler tasks, which required nothing more than extermination of a population, as they were incapable of strategy due to their lower intelligence. (AUDIO: Rewind) They were capable of reconstructing themselves from any material, including the bodies of their victims, to repair battle damage. (AUDIO: Berserker)

History
Berserker Daleks were used to wipe out entire populations during the Time War. (AUDIO: Remnants) The War Doctor encountered them when they raided the planet Lacuna, however he arrived too late to stop the invasion. In a desperate gambit, he created a time loop of the last day before the planet was devastated using his TARDIS and spent hundreds of repeats trying to identify a timeline to save Lacuna. He was finally convinced to break the loop and leave by Ignis Abel, though he promised to try to think of a way to return and save the people in the 20 seconds left before the Daleks devastated Lacuna. (AUDIO: Rewind)

The Science Division tested a Berserker by unleashing it on a Time Lord research station staffed by young Time Lords. It wiped them all out save two, Cresta and Teblin, who were rescued by the General, Cardinal Rasmus and Commander Veklin. After they discovered a weakness to the Berserker, that it’s organic component could he temporarily frozen by experimental preservation technology, the Dalek scientists boarded to halt the test however found the Berserker now uncontrollable, resulting in it killing them. Afterwards Teblin caused the station’s engines to explode, killing the Berserker. (AUDIO: Remnants)

After occupying Orrison and relocating it across space, the Daleks used its people to manufacture Berserker casings and then mutated them into Dalek mutants to occupy them once they were too weary to work. The planet and all the Berserkers on it were destroyed when Leela, Rasmus and Veklin brought down the temporal barrier around Orrison which, due to an error with their timing, detonated hundreds of TARDISes poised to attack the planet. (AUDIO: Ambition’s Debt)

Berserker Daleks were part of the Daleks’ attack on Sunspire which wiped out most of the population. One became trapped in a bunker containing the natives’ gene bank and was left there for centuries, attacking the walls of the facility as it became increasingly insane. It was disturbed when a team of survivors along with the War Doctor and berserker-class cyborg Case entered the bunker, killing most of the survivors. Upon discovering Case it attempted to use her to reconstruct itself however she was too much for it, resulting in the two merging to become something new. (AUDIO: Berserker)

Berserker Daleks were used during the Daleks’ attack on Memnos, being ordered to break into a Dalek harvester which the Doctor and Case were hiding in. (AUDIO: Memnos)

Behind the scenes

 * James Johnson released a closer look at the Berserker Dalek design featured on the cover of Manoeuvres. Whilst Berserker Daleks had previously featured on the cover of Comrades-in-Arms, this closer look elaborated on some design elements unique to these types of Daleks, such as a buzzsaw attachment, a heavy multiple-barrel firearm, tank-like tracks and exhausts on the rear. Johnson's writeup indicates the saw attachment is able to cut through Silictone and Chronosteel.