Darth Abusus was the apprentice of Darth Massacrus before his renunciation of the dark side. He hated his old master after this and sought only revenge. It was finally granted to him during the Second Galactic Civil War when Abusus defeated the now Terann Ulkar in a duel. He was then made a Sith Master and remained in the position for many years before finally dying of disease in 148,294 ABY.