Rutan Empire

The Rutan Empire was the hive minded empire of the Rutan Host, ruled by the Rutan Queen.

History
Based on their homeworld, Ruta III, the Rutan Empire once controlled the whole of the Mutter's Spiral. However, after engaging in their war with the Sontaran Empire, they were driven to the fringes of the galaxy.

In the early 1900s, the Rutan Army made a series of strategic withdrawals to specific strongholds, viewed by the Fourth Doctor as them losing the war. The Rutan Battlefleet at this time sent a scout to Earth, which was viewed by the Rutans as a strong point. However, the Doctor and Leela killed the scout and destroyed the approaching Rutan Mothership, convincing the Rutans that Earth's system was too dangerous to occupy. (TV: Horror of Fang Rock)

In 2009, the Tenth Doctor suspected that the tables had turned, with the Rutan Empire now gaining the upper hand in the war. (TV: The Poison Sky)