Six thousand years before Sora and Shiro were even a blink in the history of Disboard, war consumed the land, tearing apart the heavens, destroying stars, and even threatening to wipe out the human race. Amid the chaos and destruction, a young man named Riku leads humanity toward the tomorrow his heart believed in. One day, in the ruins of an Elf city, he meets Shuvi, a female exiled "Ex-machina" android who asks him to teach her what it means to have a human heart.
Genius gamer siblings (plus being NEET & hikikomori) Sora and Shiro are known as the undefeatable “__” (blank). Their talents and skills are so good they are considered as urban legend. One day, a young boy named Tet appears before them, claiming to be the “God” of another dimension where Sora and Shiro are summoned to, in which no violence is allowed and everything is decided by a game. Of the 16 different races residing in this world, “Humanity” is the weakest. After having the vast majority of their lands captured by the other races and being driven to the brink of extinction, Sora and Shiro challenge these one-of-a-kind battles of the intellectual powers in order to save Humanity.