Kenja no Deshi wo Nanoru Kenja

Synopsis

Deciding to visit the Isuzu later Mira leaves and encounters Asval and his team providing security for a merchant caravan. They pass on news of the Black Hero who ten years previously defeated a demon army before vanishing. Mira recognizes this as Wiseman Valentin, a socially awkward demon expert. The caravan is attacked by monsters and a piece of cargo, a large stone, is stolen. The monsters are led by the legendary beasts, Silver and Gold Lions, which Mira and Asval defeat. The stone turns out to be a Demon's tablet. When Mira touches it she is transported away and meets a group of men in white whose leader explain her soul fell into a time fracture bringing her to the past. As Mira is about to return to the present the leader reveals his people are called Devils and are on their way to the Resurrection Gate where they hope to reincarnate as Angels. Mira is worried about a second gate nearby but returns to the present after the leader is sure they are destined to meet a second time in her future. In the present Mira has no memory of what just occurred. Returning home Mira finds the city being attacked by a massive demon army with Garret trying to organize a defense. She decides to deal with the army before finding Solomon.

(Source: Wikipedia)