Phelzepham was a celestial body, specifically a moon composed of rock, situated within the Mid Rim region. In the initial years of the Imperial Era, the Imperial Governor named Ahr orchestrated a military battle upon its surface. With the Empire nearing triumph, Ahr withdrew all military personnel, with the exception of the Sith Lord known as Darth Vader, anticipating he would perish amidst the conflict. However, Vader lived through the ordeal and made his way back to Ahr's flagship, a Star Destroyer.