Zegapain

Kyou Sogoru believes he is an ordinary high school swimmer in the peaceful seaside city of Maihama. Then Shizuno Misaki pulls him into another reality, where he pilots a Zega in a desperate war fought by Cerebrum against the Gards-orm.

The deeper Kyou becomes involved, the less his everyday world makes sense. Memories conflict, deaths refuse to behave as they should, and the boundary between physical reality and digital existence begins to collapse. To protect the people he loves, Kyou must uncover what happened to humanity and decide what it means to keep living when even his own existence may not be what he believed.