A Unicomplex is a vast decentralized control structure spanning across hundreds of kilometers, used by the Borg Collective. The Borg Queen typically resides in unicomplexes, when not attending the assimilation of a new species from a Borg ship.
- A unicomplex is discovered in the Delta Quadrant by U.S.S. Voyager's Delta Flyer in 2375.
- In 2378, an alternate future version of Kathryn Janeway infects the Queen and complex with a neurolytic pathogen, leading to the Borg Queen proceed with the self-destruction of the Unicomplex to prevent the virus from spreading. This diversion allows Voyager to use the Borg Transwarp network to return to the Alpha Quadrant.
- The steady decline of of Borg activity since the unicomplex destruction leads Starfleet to the assumption that the Borg threat has been eliminated permanently. In 2385 the Borg task force is dismantled. Annika Hansen resigns her Starfleet commission to protest the decision.
- In 2410, a unicomplex has been constructed to serve as a command center for the Collective's invasion of the Alpha Quadrant. A second Unicomplex is also discovered in Fluidic Space.
- “Fluid Dynamics”: The Borg have constructed a Unicomplex in Fluidic Space to serve as a beachhead for a new offensive against the Undine.
- “Into the Hive”: Players infiltrate the Unicomplex and battle the Borg Queen.
- “Hive Onslaught”: Players battle a Borg fleet and the Borg Queen's Octahedron in the space around the Unicomplex.
- “Borg Disconnected”: Players assault a Unicomplex in the Delta Quadrant to prevent the Borg Queen from reintegrating liberated Borg vessels back into the Collective; the mission is complicated by the arrival of Voth and Undine forces.
- “Butterfly”: In an alternate timeline created by the use of the Krenim temporal weapon, the Borg have established a massive Unicomplex around an assimilated Romulus.