Cogen V

Cogen V was the fifth planet in the Cogen star system, in Mutter's Spiral. It was the homeworld of the Cogenians.

History
In 2368, the combined Borg–Cyberman fleet assaulted Cogen V and began assimilating the world and its people. In the process, they abducted the entire Cogenian population. However, the Cybermen then turned on the Borg, battling in the streets. The Cybermen took the Cogenians for cyber-conversion.

The USS Enterprise followed the fleet to Cogen V, but discovered that it had abruptly changed course and left. Commander William Riker, Lieutenant Commander Data and Lieutenant Worf, together with the Eleventh Doctor, Amy Pond and Rory Williams beamed down into a Cogenian settlement, discovering it left in flaming ruins. Surviving Cogenian sentry drones attacked the group of arrival, but were soon shot down. They discovered Borg and Cyberman bodies left on the surface and soon learned on the battle amongst their enemies. (IDW: Assimilation²)