The world has changed recently. Ten years ago, a force field known as Hell's Gate had closed off a vast part of Tokyo, and several people have gained paranormal abilities that permit them to wield tremendous power. Hei is one of those people; alongside his associate, Yin, he works for one of the many agencies that are hoping to find a way through Hell's Gate, in hopes of harnessing the immense power that created it. Currently 10/10