Rui Tatsumi features in the Halloween special as a high school student and actor. He joins other characters in performing the song "Pumpkin Mate♪" as part of the Halloween festivities, while also assisting with preparations for the celebrations, which include possible prank coordination. Within a special drama track, Nanjo Koki unexpectedly drafts Tatsumi as back-up help to create ghost costumes for a planned prank on the First Dorm residents. Tatsumi arrives at the Second Dorm alongside Kitahara Ren after Nanjo summons them to the ongoing costume-crafting session.