Under the surface of this seemingly ordinary world, a supernatural force called "different blood" surges. A very small number of human beings contain this liquid energy, which gives the host physique, speed and strength far beyond those of ordinary humans. People with different blood activate their potential through the "bloodletting" ritual, and their abilities are classified from S to E. The higher the level, the more dangerous the ritual is - the rumored S-level even requires piercing the heart or cutting the throat to show its true form. Low-level ones can only strengthen their physical strength, while mid-level ones can coagulate their blood into soldiers. The blood of the top-level S-level aliens can cover the whole body, forming a set of "alien blood suits" containing terrifying power, which can be called a humanoid strategic weapon. Most ordinary people know nothing about it, and their world remains peaceful and ordinary.
However, the hidden superpower war never stops. The militarized organization "A. R. E. S." Was jointly founded by the original S-class aliens. They gathered strength and gradually took control of the global order, firmly believing that their iron-fisted rule was the only way to protect the world from chaos. In contrast, the resistance organization "Rounder" rose in secret. They were composed of aliens who opposed the tyranny of Ares. They had a loose structure and operated as bounty hunters through the dark network, aiming to destroy Ares at all costs.
The secret war between the two camps constitutes the true background of this world.
