Demon Slayer: I’m Muzan’s Most Loyal Hound

In the chaotic Warring States era, a forsaken child quietly grows up in the shadows of the Tsugikuni family. Tsugikuni Soya, Yoriichi’s half-brother, is stripped of his family name for having no talent for swordsmanship. After his mother coughs up blood and dies, he vows to sever all family ties. At twelve, on the brink of death, he meets Muzan Kibutsuji. With the words, “I will follow you, my lord, through fire and water,” he pledges his loyalty and becomes the sole “demon retainer” under the Demon King.

Across a thousand years, he is the shadowy chronicler of Muzan’s faction. From a hidden blade in the Warring States era to the floating world of Edo, he establishes the rules of the Twelve Kizuki and searches for the Blue Spider Lily. From the dawn of the Meiji era to the final days of the Heisei era, he faces the legacy of Sun Breathing and contends with Tamayo for a century. With Shadow-Eroding Breathing, he shatters the light; with Moonshadow Heart-Devouring, he swallows hope. He even stands alongside his elder brother Kokushibo, now a demon, bound together by hatred and a strange kinship.

When Tanjiro Kamado kindles the flames of Sun Breathing, the battle at the Infinity Castle begins. Soya uses his body as a shield, building Muzan’s final line of defense. Amid the forbidden art that buries the world in shadows, he fades into darkness, leaving only a thousand years of obsession behind as the ashes of history. This is both the redemption of an abandoned child and the final song of a loyal soul. The night is long, but a loyal soul never dies.