From UFStarfleet Wiki
The USS Redeemer first encountered the Nevwa Alliance when it was pursuing a True Federation starship inside the Windsor Galaxy. A Nevwa Battlecruiser decloaked and beamed it aboard before the Redeemer could react.
The Nevwa Alliance is the second superpower of the Windsor Galaxy. They are the Mendari's arch enemy. The Alliance is made up of several different species and planets which all serve the Alliance's cause. They seek to free themselves from the "Mendari Overlords" whom they see as overzealous conquerers. The Mendari's practice of "protecting and governing" planets which they see as defenseless or anarchical has caused the Alliance to view them in this manner.
The Nevwa Alliance devoted much of its time and resources researching and developing large, massive starships called Nevwa Battlecruisers. These ships are 2 1/2 times the size of a Federation Galaxy class starship. These ships serve as a sort of city-ship and as massive carriers. They are capable of carrying starships, fighters, and runabout-sized craft, as well as housing thousands of personnel.