The Indomitable Domain of Terlath the Tenebrific

From the introduction: During his descent into depravity and charnel horror, the renowned archmage Reynaldo Lazendry trained several students in the wizardly arts. Most of them shunned his turn towards evil, but some embraced it. A handful of these dark apprentices escaped the calamity that sealed the dungeons of Reynaldo Lazendry and went on to varied careers in villainy.