Harukanaru Toki no Naka de 6

The manga adapts the game of the same name, and centers on heroine Azusa Takatsuka. Azusa is high school girl who one day finds herself in a world that appears very similar to Japan's Taisho period. She quickly runs into trouble, but is saved by a man named Darius, who calls himself a "demon."

(Source: Anime News Network)