This quest is not available in game.
Give Mokvar your Dreadmist Mask and Dreadmist Robe.
A truly amazing story, <name>! You have my thanks, and the heartfelt gratitude of all who were involved, I can assure you. Through your efforts we are delivered from the mistakes of our past.
As to your reward, I believe I have a few things that you have definitely earned and will truly enjoy.