KADO: The Right Answer

Japanese government negotiator Koujirou Shindou has been absorbed into a giant 2km long cube known as Kado. Inside, he meets a being called Yaha-kui zaShunina, who seems to possess powers beyond humanity's ability to comprehend. Who is this being, and what are his plans for humanity? Shindou agrees to become this creature's representative as it begins its negotiations with the Japanese government.