Melkhior the Ancient

Melkhior was the first Necrarch created by W'soran. In his tower in the Forest of Shadows, he continued W'soran’s work on the Grimoire Necronium, his visions of the future growing more disturbed over the centuries as his sanity cracked further and further. Eventually, his visions grew so vivid they could not be depicted in prose, and he began painting on canvases of skin. His dungeons were filled with the living for him to torment. He often turned his mad attentions on his loyal servants as well, until Zacharias challenged him and, eventually, defeated him. Melkhior was not destroyed, however, but slumbers whilst regaining his strength so that he can return to revenge himself upon his wayward student.

Source

 * Warhammer Fantasy RPG 2nd ED -- Night's Dark Masters (pg. 62).