In this place where everyone wants to live for production, the only way to survive is to kill each other, and the killer can get benefits in the middle. This is also the meaning of the killer's existence, he lives to kill.
In the world of war, many people have formed some killer organizations. One of the most prominent organizations is called "Heavenly Killer". This killer organization is divided into six levels: God, Ghost, Blood, Shadow, Demon, and Madness. The price of killers at each level is definitely different. Someone wants to kill someone, and then reports the name of the person to be killed, and a level is determined based on the value of that person. However, there are only two killers in the god and ghost levels. They basically don't take action, but they will see blood when they do.