Ryouko Natori
About
Appears in Shi wo Utau Seiza (Constellation that Sings Death). Ryouko worked at the inn one year prior, and fell to her death when the suspension bridge collapsed under her.
Ryouko was Rei's older sister, and was also friends with all the current guests at the inn. The argument between her and Orie was a result of Yuuko's meddling, with Orie mistakenly accusing Ryouko of stealing a ring from one of the guests. Ryouko's actual spirit appears when Yuuko is trying to kill and frame Rei, and pushes Yuuko off the cliff in the same spot where she died.