Keigen Omotada and Usagihara Tachi came from the derivative world B-6257. They observed that all the protagonists in the main world were wiped out and fought for the survival of their own world. They chose to trade with the main world and achieve a happy family reunion. So I came to the main world and became classmates with the three people from high school. At that time, everything had just begun.
Intention: Stand upright and be a good person