Where can I know the story of pink book and red robe in Dungeons and Dragons? Read some dnd novels, which often appear.
The red shroud is the daughter of MacKanhut and the hostess of Duan Yu. Her goal is to replace mom. As for the pink book. . . . Let's just say, don't think too much about this matter. It's just an ordinary H spell book under the cover of the secret goddess. If you want to know more details, just look at the background information of Dungeons and Dragons (preferably Forgotten Country).