Command Dalek

Command Daleks or Dalek Commanders were rank of Dalek serving the role of commander. They were subordinate to the Supreme Daleks and typically used casings identical to the Dalek drones under their command. (PROSE: Prisoner of the Daleks, Birth of a Legend) They commanded their own ships, designated command ships or base ships. (COMIC: Abslom Daak... Dalek Killer, Star Tigers)

Saucer commanders, distinguished by their black domes and alternating black panels on the base unit, commanded Dalek saucers. (TV: The Dalek Invasion of Earth, COMIC: The Threat from Beneath, PROSE: Mission to Galacton

History
In the 23rd century, the Battle Commander Daleks were a group of twelve Daleks who directed the Dalek war efforts. They were subordinate to the Dalek Emperor and Davros. (GAME: Dalek Attack)

The Kangring Squadon which participated in the invasion of Earth's solar system in 2400 were led by the Red Commander. (COMIC: Invasion of the Daleks)

In the 26th century, during the Second Dalek War, a Command Dalek commanded a Dalek base ship with a crew of 1,000 Daleks on the planet Mazam. (COMIC: Abslom Daak... Dalek Killer)

A trio of Dalek ships, including a Dalek Commander's command ship, pursued Taiyin's space yacht to Draconia only to be destroyed by Abslom Daak before he touched down on the planet. (COMIC: Star Tigers)

A bronze Command Dalek was the bronze Dalek commander of the Dalek base on the planet Arkheon to exploit the Arkheon Threshold using slave labour during the Second Dalek War. This Dalek ordered the captain of Wayfarer, Jon Bowman, be taken for brain excoriation which would kill him. The Tenth Doctor admitted to the Command Dalek who he was and was placed at Bowman's cell. It accompanied Dalek X to find the Doctor's TARDIS with the Temporal Research Team, the Doctor and the surviving bounty hunters to Hurala with the Dalek Inquisitor General's flagship called the Exterminator. The Command Dalek was destroyed when the fueling station exploded while attempting to exterminate Bowman near the TARDIS. (PROSE: Prisoner of the Daleks)

A Red Dalek Commander led the Red Extra-Galactic Squadron on various missions throughout numerous galaxies. In the 40th century, (COMIC: The Brain Tappers) the Squadron returned to Skaro for the re-election of the Dalek Emperor. However, the Commander had become disillusioned with the Emperor due to the Daleks' persistent failure to defeat humanity. It spoke out by denouncing the Emperor and demanded that a better leader be put in place. The Emperor was furious as this display of insubordination and turned the Black Dalek Leader against the Squadron. The Commander and the rest of the Squadron were destroyed. Yet secretly the Emperor acknowledged that the Commander had been right about its shortcomings and it resolved to improve and rebuild itself. (COMIC: The Secret of the Emperor)

A Dalek Commander was in charge of the Dalek operation on the planet Ercos to test the Dalek driller. He exterminated a Dalek for failing to capture Ticon. The Dalek Commander was killed by two Daleks for failure. (COMIC: The Dalek Revenge)

The Vega VI Dalek commander was the Dalek commander of the invasion of the planet Vega VI to collect large amounts of veganite, a mineral that could be used for Dalek plans. He reported to the Supreme Dalek, leading the Galactic Attack Sphere Head, that the slaves at Vega VI had stopped working and began resting and eating. (AUDIO: Invasion of the Daleks)

A bronze Dalek served as Dalek Commander of the Seventh Incursion Squad whose mission was to wipe out the Mechonoids on Magella. He commanded from on the battlefield overseeing the field from vantage points. After the Mechonoids were exterminated, the Commander returned as ordered to the Dalek Emperor on Skaro. In anticipation of the coming Last Great Time War, the Emperor named the Commander Dalek Sec, appointing him as the leader of the Cult of Skaro and providing him with a new black casing of Metalert. (PROSE: Birth of a Legend)

During the Time War, a Dalek Taskforce Commander, serving under the Dalek Time Strategist, led the Dalek attack on Fergil. (AUDIO: Pretty Lies)

Behind the scenes
"Dalek Commanders were an integral part of the war effort against the Time Lords. These specifically bred mutants were connected by a private pathweb to other units across the fleet, allowing the instant sharing of tactical and military planning information. They were the successor of the earlier Battle Computers, discarding the need for non-Dalek life-forms to be utilised for their instinct and intuition."
 * Similar to Supreme Dalek/Dalek Supreme and Dalek Emperor/Emperor Dalek, the terms "Dalek Commander" and "Command Dalek" are used interchangably across media.
 * James Johnson rendered a Time War-era Dalek Commander model which was featured on the cover of Gallifrey: War Room 1: Allegiance, sporting a black and silver livery reminiscent of the earlier Battle Computer unit seen in the Shoreditch Incident. Ahead of release, Johnson released a closer look at his designs, also clarifying that the accompanying text wasn't in any way official, and that he added it "just for fun".

- James Johnson