Toilet Bound Hanako-Kun (Manga) Vol 13

Nene and Akane are rescued from the clutches of a horde of supernaturals by School Mystery No. 6... who then immediately kidnaps Aoi?! With so many School Mystery seats unfilled and the long, dark night of Urabon here at last, Aoi may be the only one who can save the school from disaster - but at what cost? Yen Press
(W/A) Aidalro