Dear Mother,
J’Zhirr finds Durnehviir already restored and waiting for him outside the building. J’Zhirr readies himself for another round but Durnehviir calls out, “Stay your weapons. I would speak with you, Qahnaarin.”
Turns out that Durnehviir is so impressed by the result of the battle, that he grants J’Zhirr the right to call his name from Tamriel should this one need an ally in battle. Durnehviir says, “For countless years I’ve roamed the Soul Cairn, in unintended service to the Ideal Masters. Before this, I roamed the skies above Tamriel. I desire to return there.”
However, Durnehviir had spent so much time in the Soul Cairn, that he now cannot venture far from it. If he stay away too long, his strength will wane until he is no more. Granting J’Zhirr the right to call his name in battle will enable Durnehviir to fly once again in Tamriel, even if it is only for a short while.
Postcards from Skyrim 