Salem
Salem is a problematic character - a villain from the early days of the Companions of the Rising Sun's adventuring career, who kept turning up, with an overdeveloped sense of vengeance. As a lich-spawn, he also implies a much greater threat - that of his master and creator, theorized by the Companions to be no less than Shinn the Sorcerer. He is furthermore himself a sorcerer of no small power, specializing in the dark arts.
After several encounters with him, the Companions believed him vanquished forever when they captured his phylactery and delivered it to the Order of the Light of ORB for safekeeping in the Zoo. There, he was used for study and training purposes, systematically being destroyed and regenerating.
However, the Companion's belief turns out to have been premature, as, when the return of the Holy Temple disturbed the wards locking the undead in the Zoo, Salem was one of the leaders of the break for freedom, accompanied by some potent allies. He himself had grown in power, wielding much more potent spells and strategies, and sporting as well a bodak's eye grafted in place of his own, which came with the bodak's death gaze.
After a long fight in the tunnels of Mt. Daneasus, he was again vanquished and his phylactery recovered, this time destined to be destroyed.