The Heir of the Ancient Artifact

The young boy, Haku, a loner in this vast world, harbors a small love for his enigmatic childhood friend, Miriam—the only person who ever truly saw him. However, the girl he loves bears a mysterious fate, being relentlessly targeted by the rulers of the land. To protect her from the looming threats, the boy forms a pact with an ancient artifact. Despite the toll it takes on his body, he annihilates those who dare harm her, one after another. Unbeknownst to him, their fragile, wounded love is slowly being consumed by the overwhelming darkness of the world. Guided by a bizarre and mysterious “mask” passed down through the ages, this is a transformative dark fantasy tale. https://www.cmoa.jp/title/325625/