The Forsaken Betrayer

In the Daedric ruin of Hadrumnibibi, I met the witch Silhaenil. She asked me to help her exact vengeance on Uridimmu, a dremora who betrayed her and then fled to a plane of Oblivion. I agreed. Silhaenil told me to prepare well and then let her know when I'm ready to be transported to Uridimmu's general location.

Before sending me to the plane of Oblivion in which Uridimmu is hiding, Silhaenil gave me an amulet. She told me that I will return to Tamriel when I put it on, but that it will only work once, and so I should not do so before killing Uridimmu.

Silhaenil thanked me for carrying out her vengeance on Uridimmu.

Silhaenil was angry that I returned to Tamriel without enacting vengeance on Uridimmu.

Silhaenil is dead.