Coralyssa

Coralyssa is an NPC in Protector's Enclave who starts the class-specific quests for the Scourge Warlock. She can be found at the foot of the stairs that lead to the altar where you invoke; the altar is North and very slightly East of Sergeant Knox. If you are looking at your map, the "M" key, she's at the foot of the right hand staircase, by the statue of the lion. If you're at the altar, and are facing it, same thing.

Quests

 * In Over Your Head
 * Curses!
 * Pain and Suffering
 * Pact Blades and You
 * Meet Your Master