The Farthest Twilight

The end of the world was foreseen. Unwilling to face the end without a struggle, humanity enters the Twilight Time, mysterious region of space that appears out of nowhere, and battle against the demons that materialize from within, Vagan. Such battles frequently occurred in the underside of the world when a high school student, Shinonome Touya noticed an anomaly and wandered into Twilight Time. In there, he was assaulted by Vagan, but saved in the nick of time by a girl who fights against the end, Kisaragi Mibime. The next day, while receiving an explanation about the anomaly from Mibime, another Twilight Time appeared. Mibime immediately leapt inside to fight, but somehow, a Sacrament, supernatural weapon to combat against Vagan, appeared in Touya’s hands…!? Source: Overlap