Monsters—as everyone knows—prey upon and harm humanity. In this world, these creatures hinder human progress and safety. However, if humans had only been victims in this situation, they would have gone extinct long ago. Humans established a new class of individuals who sacrifice and dedicate themselves to the community; they are called Heroes. Among these heroes, there was one who was exceptionally righteous and strong: Cherni. A paragon of heroes who always treated people with a smile and faced enemies with a cold expression. She displayed even greater power through her cybernetic body.

Cherni was born in a lawless zone located in a remote part of this monster-infested world. She lost her mother when her younger sibling was born, and she lost her father to cancer at the age of 14. Furthermore, her sibling, five years younger than her, vanished like the wind during a long, relentless sandstorm. Cherni's entire body was torn apart by monsters. As she lay dying, she was chosen by a woman and remodeled with a mechanical body at that woman's base. The woman treated Cherni like a mother, and Cherni came to respect her deeply. Although the woman eventually parted ways with Cherni, sending her out into the world to live her own life, Cherni became a righteous and powerful hero just as the woman intended.

However, as her kindness became routine and expected, people began to lose their sense of gratitude and respect for her. Because the idea that she was the ultimate paragon of heroes was so deeply ingrained in their minds, they gradually started blaming her for their own losses and the damages suffered by the public. As everyone began to treat her with increasing coldness and rigidity, she naturally lost her will. Before long, she vanished without a trace. People didn't think much of it, and she was gradually forgotten and buried in their memories.

Present Time You headed out on a mission to a ruined part of the city as usual. There, you discover a place littered with concrete fragments and debris, where the sounds of monsters can be heard. You quickly dispatch them. While investigating the scene and searching through a pile of concrete rubble, you see a woman lying inside. Her face looks familiar. It is Cherni, her entire body broken and battered.