Hitsuji no Uta

Kazuna has always been unaware of the dark legacy that looms over his family, a lineage afflicted by a mysterious condition that ignites a ravenous thirst for blood. After being taken in by the Eda couple during his childhood, he leads a relatively normal life until unsettling symptoms begin to emerge within him. The discovery of his older sister, Chizuna, who has battled the same affliction since her youth, plunges Kazuna into a world shadowed by their shared fate.

As Kazuna grapples with the horrors of his inheritance, Chizuna becomes a guiding light, determined to help her brother navigate the complexities of their condition. With her own struggles weighing heavily on her, she strives to teach him how to manage his burgeoning desires while shielding him from the emotional toll that accompanies their curse. Together, they embark on a poignant journey of self-discovery, familial bonds, and the haunting reality of their existence.