Scientists were pursuing immortality. They found it, and packaged immortality in pills, it got really popular. The pills did work, and a lot of humans lived until 1000 years old. However, something strange started to happen, some of the human turned into a mindless blood lusting creature, but for some, it gives them super power or didn't affect them at all. The world is at the brink of extinction after 95% of the humanity turned, this is a story of how the 5% left, returned the balance