The purple book pile that you can click on to get Blur. I tried using it when I got in, and kept failing due to.. bad pathing. My character just walked up to it from 3-4 different angles, then I went ham on killing books. Eventually after finishing the quest, I decided to try figuring out what the book pile did, and after a good while of failed pathing it eventually let me get a blur.
TLDR: purple book pile in the quest for blur seems to be difficult to reach