"I'll be the final killer in this world to end killing. Killing will only become history after I die. There is no one else who could do this but me." In a world where killing is already a common occurrence, a reaper will rise. An assassin's blood stain the skin of a young girl living a simple life. With her identity buried in her past, she kills every killer on her list without hesitation. Her journey inside the tower will lead her to an immortal who will guide her in changing her single-sided mentality. As the two protagonists attempt to escape the deadly games, they will soon delve into the history of the game. In particular, they will learn what it means to be a Descendant of Death.