World Trigger

Yuma Kuga is a foreign student who has just arrived in the city of Mikadoshi. Osamu Mikumo, another student in his class, is in charge of taking care of the newcomer, but on the first day after school, they witness the opening of a breach in reality and the appearance of a Naver, a race of invaders from a parallel world. Osamu intervenes and uses a weapon from enemy technology, the Trigger, which allows him to call upon special powers. This young student with a docile appearance turns out to be a member of BORDER, the elite soldier organization that contains the invasion of the Navers. But inexperienced, Osamu finds himself in a difficult situation and is then saved by the frail Kuga, who also possesses a Trigger...but with a power far superior to Osamu's... What is Kuga's true identity? Who is he really, and why come to this school?