Dalek Prime Strategist

The  was a veteran Time-Sensitive Dalek drone encountered by the Tenth Doctor when a paradox caused him to land on a version of Skaro which did not remember having fought in the Last Great Time War, but was facing attack from the Hond.

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. 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) 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)

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 Golden 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)