Shirotabi was a rabbit that was cared for by the school pet keeper, Mio. After its death, Mio decided to bring Shirotabi back through a black magic ritual. The spell worked, but in the other side Shirotabi was put into a curse where it turns into a killer demon every night. Mio tried to stop Shirotabi, but realized Shirotabi did not even recognize her. It was up to Satsuki and the others to convince Mio that Shirotabi's place should be with the dead, and so Mio agrees. Mio broke the spell, and Shirotabi remained dead forever. It appears in episode 9 and makes a cameo in episode 20.