Used Bookstore (Kani-chan) is a cute character that was recently added to Chiikawa as a new character.

Originally a supporting character, like other mob characters, it was depicted in all grey without a face.

However, in the story, this character frequently appeared as a grey mob character and as a used bookstore clerk. Eventually, after deepening interactions with Momonga who came to buy old books, the character developed a personality, transitioning from grey to its current form.

As a result, there are illustrations of it together with Momonga, or taking care of the Momonga. Hence, this character is sometimes called “Used Bookstore,” and because it has something resembling crab claws on its head, it's also called “Kani-chan.”