Harukanaru Toki no Naka de 6

On her way to visit her grandmother in hospital, ordinary high school student Takatsuka Azusa is drawn by a mysterious voice through space-time into a parallel world modeled on the Taishou Era. She arrives in an Imperial Capital Tokyo where beings called Onryou have been running rampant in recent years, and where the Imperial Army's Onryou Subjugation Organisation struggles to maintain order. An oracle has identified the need for Ryuujin's shrine maiden—and the summoning ritual the Imperial Army performs produces Azusa. Before she can process any of this, a young man named Darius introduces himself as a demon, takes her to the Enchanted Forest west of the city, and shelters her in his estate. The Imperial Army wants her. The demons want her in their corner. Azusa is caught between them.