Hyakki Yakai: Kizuato Chigiru Otometachi

Takami, a high school girl, is forced to go on a “test of courage” with Hinako, a girl at the bottom of the class caste. They find countless spirits drifting in the mountains and try to escape, but Hinako betrays them and leaves Takami behind. Takami is in danger, until a spirit who calls itself “Itsuki” appears! A night of mystery begins between Takami and Itsuki, who share a “common wound”…

(Source: Gangan Joker, translated)

Note: Chapter count includes an 0.5 chapter and an epilogue.