Toying with the Dead

Walkthrough
If the Dragonborn chats with Vekel the Man at the Ragged Flagon, the innkeeper will mention that he has a buyer interested in the journals of a mad mage, Arondil, and that the journal is in four parts. He also relates that while Arondil once lived in Dawnstar, he is now reportedly holed up in Yngvild.

Note: Exploring Yngvild will let the Dragonborn find the Arondil's Journals even without having joined the Thieves' Guild, the reward seems to differ as well.

Enter Yngvild Barrow
Locate Yngvild and enter the ice caves beneath the ruins.

Retrieve Arondil's Journals (4)
Locate the four parts of the Journal which are guarded by draugrs and ghosts.

Return to Vekel
Once all four parts have been retrieved, return to Vekel the Man at the Ragged Flagon.

Spiel mit dem Tod