A diamond-shaped vessel holding the "lair" of the Borg Queen. In 2375, the Borg Queen vessel originating from Unimatrix One travelled to Grid 532 to participate in the assimilation of Species 10026. While the Borg Queen vessel is not normally required to be present at such events, ex-drone Seven of Nine was aboard and the Queen wished to refamiliarize her with assimilation procedures. The plan was to benefit from Seven's experience as an individual to eventually assimilate Species 5618 — the human race.
The plan failed, however, as Seven refused to betray her species and she was rescued by Captain Janeway and others aboard the Delta Flyer. The Borg Queen vessel pursued the Delta Flyer through a transwarp conduit, but was destroyed when the U.S.S. Voyager collapsed the conduit with photon torpedoes.
The Borg Queen herself originated from Species 125.