Shinen kara no Kikan

Historia

"I shall wait for you at the edge of the Abyss..." That is what a mysterious man said to Sora Mukujima in one of his dreams. Sora lived a modest life together with his parents, until one day, that peaceful life fell apart. A massive tower appeared. His brother, a soldier, was unreachable. And monsters began to attack suddenly. When he was in a desperate situation, the man from his dream appeared before him. And when he woke up next, he was in an unfamiliar place. It was a different world called the "Abyss", just as the man had called it in his dream.

Sinopsis vía AniList (en inglés).