This quest is not available in game.
Take the Phylactery of Kel'Thuzad to Light's Hope Chapel in the Eastern Plaguelands.
- The Phylactery of Kel'Thuzad (Provided)
The phylactery is all that remains of the master of Naxxramas. Your better judgment dictates that you destroy the phylactery, preventing the lich from ever reforming. Thankfully, you seldom listen to that internal voice of reason.
Someone at Light's Hope will pay you hugely for this artifact. Who cares if Kel'Thuzad regenerates to full power?