Promellians were a humanoid civilization native to somewhere in the galaxy's Alpha or Beta Quadrants. At their height, the Promellians were warp-capable, technologically advanced space-farers. By the 24th century, the Promellians were extinct, the result of a decline begun a thousand years prior. The war between the Promellians and the Menthar resulted in the mutual extinction of both races. The final battle was fought in the remains of the planet Orelious IX, in the late 14th century. (TNG episode: "Booby Trap")