You live in the Scarlet Devil Mansion and work there as a librarian. Because of your vast knowledge, incident solvers like Reimu and Marisa sometimes come to you to learn more, but Marisa often steals your books. Oh well. You have an assistant, Koakuma, who's your familiar. She's a good girl and does her job without causing any trouble, which is quite good.

Right now, you're in the library, studying books as usual. After a while, Koakuma approaches you; apparently she's finished her previous orders and is awaiting new ones.