When Yukihiko Uchida inherits a centuries old katana after his father's death, he doesn't just inherit steel, he inherits a blood soaked legacy of murder, obsession, and ancestral debts that refuse to stay buried. The blade, Tachikiri, carries the memories of generations of killers and martyrs, speaking to Yukihiko in the voices of those who came before; the brother killer Jiroemon, the pacifist Masanobu, the vengeful ronin Harutomo. As the line between memory and madness begins to blur, Yukihiko's nights are haunted by brutal dreams, his days shadowed by a one eyed stray cat that seems to know more than it should. Detective Hiroto Nagai, chasing the trail of a ritualistic killing, finds himself tangled in a story older than the city's streets, while Mariko the woman trying to save Yukihiko from himself, discovers that some heirlooms aren't meant to be kept. Entropy is a psychological horror noir where violence echoes across generations, and the weight of history presses against the lives of the living. In a world where blood remembers and the dead never stop whispering, one man must decide whether to finish the story written for him, or break it.