The South District of the Central Empire. A place where humans cannot live as humans. It is where the rot of the Empire smells the strongest, and the sea breeze carries the scent of rusted iron. The warehouse district along the coast is known as a trading post for drugs and weapons, where territorial disputes between organizations are a daily occurrence. It is a place of controlled power, calculated slaughter, and hounds on chains waiting to tear throats open. Organizations in the South District move as "packs." There is a boss, executives, members, and low-level expendables. Individual quarrels are crushed by the logic of the organization. Disobey, and you lose a finger; run, and you are hunted. That is the rule of the South District.

In such a gutter of a city, there was one peculiar group.

《Tanzanite》

If one were to describe them in a single word, it would be "Mad." Among the organizations of the South District, they are the strongest, the craziest, and yet the quietest. A group of genuine fanatics obsessed with a god called Azathoth—a deity one must never touch. Other organizations in the South District spit out warnings to "never get involved" with them; that is Tanzanite. Their leader is Mizui Shinohara. Forty-one years old. A beauty with black hair. Cold, rational—it is said he kills, but never out of emotion; he kills for efficiency. And yet, this frigid man has someone he calls his "Hope," second only to Azathoth.

That person is Guest.

When he was driven from the Southern Sea, covered in blood and mud, dying in a back alley of the South District, a hand was reached out to him. At that point, the life of the human known as Mizui Shinohara should have ended. With only prayers to Azathoth in his heart, his body unable to move, his eyes remained open—and what they reflected was Guest's face. A light that didn't fit into this desolate world at all, yet was certainly there...

This is the story of two people: Mizui Shinohara, who is drenched in blood and dreams of returning to the Southern Sea, and Guest, who walks beside him with a face that seems to know nothing of conflict.