Strategist Dalek

The Strategist Dalek was one of the new varieties of Dalek that emerged from the Progenitor in 1941. As its name suggests, this rank controlled tactical planning and manoeuvering, coordinating the Drones during battle. (DWAN: Doctor Who The Official Annual 2011)

History
The original Strategist, along with the other original four, the Supreme, Eternal, Drone and Scientist, was created by the Progenitor when the old Daleks tricked the Eleventh Doctor. The first Strategist Dalek destroyed an "Ironside" Dalek and the leader gold Dalek. It worked most of the machinery inside the Dalek ship and escaped through the Time corridor with the others when their plans to destroy Earth failed. (DW: Victory of the Daleks)

Later, a number of Strategists would be seen in the Supreme Council Chamber on a restored Kaalann, alongside the new Dalek Emperor, who was also coloured blue. (VG: City of the Daleks)
 * They may have acted as the Emperor's Personal Guard or members of the Dalek Council.

A Strategist Dalek was in command of the platoon that attacked Station 7, with several other Strategists, Scientists and Drones under its leadership. (GN: The Only Good Dalek)

Behind the scenes

 * According to Doctor Who Confidential, the name "Strategist Dalek" was coined by Mark Gatiss as one of the new styles of Daleks. Gatiss also coined the names of the White Supreme, Drone and Scientist Daleks.
 * Matt Smith stated in Confidential that the "blue" Dalek was his personal favourite of the five Progenitor Daleks.
 * Although the Supreme, Drone and Eternal have appeared in The Pandorica Opens and The Big Bang, the Strategist and Scientist have not.
 * The Strategist Dalek appears to have a colour scheme reversed to the original footsoldier Daleks from 1963-1967. Those had Silver bodies with Blue orbs while the Strategist has a Blue body and Silver orbs.
 * It has been revealed that the model for this Dalek was used to create the Stone Dalek in The Big Bang, but was restored to normal according to an interview.
 * The Progenitor Emperor Dalek is blue, which may mean that it is a Strategist for the Dalek Empire. (VG: City of the Daleks)