Vessel One of Two Unimatrix 8472

The Vessel One of Two Unimatrix 8472 was a Borg starship, a unimatrix command ship in Collective service in the 2400s decade. Along with Vessel Two of Two, Vessel One of Two was assigned to Unimatrix 8472, stationed in fluidic space. 

Service history
In 2409, the Federation, Klingon Empire and Romulan Republic agreed on a joint incursion into fluidic space to remove the Borg presence from that universe in order to pacify the native Undine. The mission was led by Rear Admiral Tuvok aboard USS Voyager. The multinational task force found a unicomplex nestled between fluidic globules. After destroying the local Borg diamond, the Undine attacked Unimatrix 8472, engaging and destroying Vessel Two of Two Unimatrix 8472 while the Allies retreated.