Harukanaru Toki no Naka de Ultimate

On the first day of a new school term, high school student Akane Motomiya, her classmate Tenma Morimura, and their younger friend Shimon Nagareyama are pulled through a mysterious ancient well and deposited in Kyo — a parallel world that mirrors Heian-era Kyoto in every detail. A young heir of the Star Clan named Fujihime informs Akane that she is the Ryujin no Miko, a spiritual guardian summoned to protect Kyo from the ambitions of the Oni Clan. Eight men known as the Hachiyo are bound to serve her — and among them are Tenma and Shimon. Bewildered and overwhelmed at first, Akane gradually finds her footing in this ancient world, discovering both her own resolve and the depth of the bonds forming around her.