Dalek Prime Strategist

The  was a Time-Sensitive Dalek who served as advisor to the Emperor of the Restoration in the Restoration Empire that had never fought in the Last Great Time War, created by the Tenth Doctor's alterations to history during the Dark Times. He claimed to be the oldest Dalek in existence.

Mutant
The Strategist's Dalek mutant form was purple with a single yellow eye. (COMIC: Defender of the Daleks)

Casing
When the Doctor encountered the Strategist, he operated a battered and rusted Dalek War Machine casing. This casing was predominantly silver, which grew rusty over time, with blue sensor globes and weapons platform boxes.

He did not upgrade it for a newer model with flight capabilities. He claimed to be wearing the relic with pride, repeatedly explaining to the Doctor that he viewed its wear and tear as his battle scars. However, the Doctor later realised that this was a lie the Strategist told himself to make it easier on him, when actually, being confined to his painfully damaged casing was a punishment ordered by the Emperor for the failure of one of his plans. (COMIC: Defender of the Daleks)

Origins
The Dalek Prime Strategist once claimed to the Tenth Doctor that he was "older than the Emperor himself", to which the Doctor replayed with a skeptical quip, (COMIC: Defender of the Daleks) in accordance with accounts which portrayed the Golden Emperor as the first-ever Dalek. (COMIC: Genesis of Evil) However, some accounts held that the Dalek Emperor who ruled the Empire following the Civil War, and who acted as the Prime Strategist's superior, was not the same individual as the original Golden Emperor, but a later pretender to the throne, the Emperor of the Restoration. (PROSE: The Guide to the Dark Times) Melody Malone merely recorded in The Dark Times Times that he had "existed for a very long time", calling him "ancient". (PROSE: The Guide to the Dark Times)

As deduced by the Tenth Doctor, at some point, one of the Prime Strategist's schemes failed spectacularly. The Emperor, as punishment, confined the Strategist to his old, ruined casing, forbidding him from upgrading to a more modern and sturdier travel machine. (COMIC: Defender of the Daleks)

Invasion of Islos
The Prime Strategist advised the Emperor during the invasion of Islos. Once the Archivians appeared to surrender, he and the Executioner accompanied the Emperor into the Archive of Islos, only to find it emptied. The Chief Archivian revealed they had bargained with an Entity from outside of time and space for the safety of the Islosian population and the Archive. It showed them what the Strategist recognised as a portal through space and time and revealed it had offered their rescuer the Daleks in return. The Entity emerged from the portal (WC: The Archive of Islos) and began attacking the Daleks, forcing them to flee Islos. (WC: The Sentinel of the Fifth Galaxy)

Flight from the Entity
The Daleks withdrew to Skaro, pursued by the Entity. The Entity began attacking the planet, forcing the Emperor to order the evacuation of all forces when the Daleks’ weapons proved ineffective. The Strategist advised that the evacuation was failing and the Daleks had to escape. With the Emperor silent after realising the home planet had been lost, the Strategist organised the Daleks‘ flight.

In search of reinforcements, the Strategist activated the Sentinel of the Fifth Galaxy who guided him to a dormant army of ten thousand Daleks. He was alarmed by the Sentinel insistent referring to him as the Emperor, and stated that he believed the android programming was defective. When the Sentinel awoke the army the Strategist ordered it to set the base to self-destruct.

However, after the army likewise proclaimed that the Strategist was their emperor, he quickly realised the Entity had arrived before him and compromised the Sentinel, and now the army. The Strategist accelerated the self-destruct and fled, pursued by the compromised reinforcements. As the Executioner’s forces engaged the Entity’s army, the Strategist advised the Emperor to withdraw again as they couldn’t sustain these losses. He defended his failure, believing the self-destruct had claimed some of the army and a portion of the Entity with them, making it weaker. He acknowledged that there would have been away to prevent this loss (namely, accepting the mantle of Dalek Emperor) but that it would not have been "acceptable… to you". (WC: The Sentinel of the Fifth Galaxy)

War with the Hond
After the Emperor had recruited the Tenth Doctor to help the Daleks fight the Hond, the Prime Strategist met the Doctor in the Dalek City. He led him to the Vault of Obscenities, which the Strategist was older than even himself. As the two made uneasy conversation, the Prime Strategist saved the Doctor from a creature the Doctor did not glimpse clearly.

Soon, they came across a Hond, who was unharmed when the Prime Strategist immediately opened fire on it. The Doctor had to trap it in an energy cage he made out of an energy weapon found in the Vault. Shortly after, the Doctor deduced the truth about the Strategist's casing, which had become even more battered in his battle with the Hond, exposing part of the Dalek mutant's face.

Eventually, the Doctor succeeded in defeating the Hond by linking together all the defence systems in the Vault of Obscenities and using them as a transmitter to relieve the Hond's pain, causing them to evaporate (as they were embodiments of suffering itself). The Daleks immediately declared that, having served his purpose, the Doctor would be exterminated.

The Doctor seemed disappointed in the Strategist for betraying him — as he had hoped, somehow, that the Strategist really was different from the rest of its kind, to which the Strategist sheepishly stated that "in the end, [he was] still a Dalek". However, he wasted no time in triggering all the weapons in the Vault at once, causing a string of explosions to engulf the Dalek City.

When reprimanded by the Emperor about the apparent backfiring of its plan to enlist the Doctor, the Strategist noted that, despite the collateral damage, the Doctor had succeeded in saving the Daleks from the Hond — and added that perhaps the Doctor, albeit perhaps a different Doctor, could still be of use to head off another related threat to Dalek supremacy. (COMIC: Defender of the Daleks)

In the Time Squad
The Strategist was a member of the Time Squad sent by the Emperor to rectify the divergent timeline and "return the situation to Dalek advantage". He served under the Time Commander, although Melody Malone suspected that as he had served under many Dalek Commanders in his day, his loyalty and obedience to this particular individual was questionable to say the least. (PROSE: The Guide to the Dark Times)

When the Time Squad captured the Eighth Doctor, (AUDIO: He Kills Me, He Kills Me Not) the Strategist saved him from being exterminated and brought him before the Commander to agree an alliance. With the Doctor, the Time Squad travelled to Wrax to analyse its altered timeline. The Strategist accompanied the Doctor to the Wraxians’ gallery, rescuing him when he was caught in the Eye of Wrax. When the Wraxians sought to use their Devolver weapon on the Daleks, the Strategist convinced the Commander to let the Doctor negotiate with the Wraxian President and later to agree to the Doctor's deal with the Wraxians, the Daleks withdrawing in exchange for the Devolver's dismantling. The Doctor had devised a theory that the temporal alterations originated in the Dark Times, which he only told the Daleks when they’d left Wrax. As the Time Lord hooked up his TARDIS to the Dalek time machine’s engines, the Strategist reported his confidence that the Doctor had been successfully manipulated, before the group travelled to the Dark Times. (AUDIO: The Enemy of My Enemy)

After the Battle of Mordeela, the Dalek Time Squad visited Velosia, who were under imminent threat from the Kotturuh. The Time Squad used this to their advantage and promised to rescue the best and brightest of their race, leaving the others to face the judgement of the Kotturuh. The Velosians agreed and the Daleks took off. Unbeknowst to them, the agreement was a ruse and the Velosians upon the ship were slaughtered, leaving the last of the race at the hands of the Kotturuh. (COMIC: Tales of the Dark Times)

Shortly after, and accompanied by the Eighth Doctor, the Time Squad stumbled across an abandoned ship hanging empty in space except databanks and a vast supply of Huon particles. The Daleks ignored the Doctor's advice to learn from the long, lost species and decided to harness the Huon particles as a potential source of energy, despite the Doctor's warnings. The Dalek ship responded negatively to the particles. The Doctor explained that while it's easy to transform any form of particles into Huon particles, it is very difficult for Huon particles to be transformed into energy. The Doctor ejected the particles, thus saving the Daleks, and explained that the ship used to belong to a race once wiped out by the Kotturuh. The Huon particles were a test to weed out the greedy and the stupid. Those races who specifically wanted to learn of the long forgotten culture would instead have gone for the databanks. (COMIC: Tales of the Dark Times)

Behind the scenes

 * Speaking of his portrayal as the Strategist, Nicholas Briggs described him as "ancient and a little bit conniving".