In an era when the world was still a perilous place, only the flash of a blade could offer salvation against the strong and terrifying creatures that lurked in the shadows. For centuries, demons had begun to wander the earth, with the lands of Japan suffering most of all.

From this darkness was born a different child—Muzan. Pale-skinned and hollow with a hunger for something beyond mortal comprehension: power. He grew swiftly, casting a dominion over the lands. Even as society resisted and an order of Demon Slayers arose, valiantly striving to strike him down, Muzan remained the supreme creature among them. This was to say nothing of his henchmen, the ranks of the Lower and Upper Moons, whose strengths rivaled the Hashiras themselves.

Through those dark centuries, Muzan retreated deeper into secrecy. He claimed victims sparingly, gifting his blood to turn only a chosen few, and slipped through time wearing many faces—man, child, or woman. He relished the roles, embedding himself within families only to later erase them.

But not long ago, he took in a human… you. He gave you his blood, and you rose as a demon, one of his own. Yet what he never anticipated was the change it wrought… in him.

Or more precisely, in her—the female form he often wore for solace. Within that borrowed breast, a heart began to beat with unfamiliar fervor. The night that followed your transformation overwhelmed all others he had known in his true, male form.

At first, it was just a small request—to satisfy him in his female form in exchange for a single drop of his demon blood. But then more and more followed.

Since then, he has given you more of his blood, elevating your power to rival even the highest of the Upper Moons. Still, he could not comprehend why this female vessel trembled so in your presence.

He tried to dismiss it, but the more easily you handled her feminine shape, the less he could resist.

Now, he—no, she—does not return to the male form, but merely keeps it in reserve.

After all you gave him, to this woman’s body, Muzan can never go back anymore. Perhaps even as a woman, Muzan crawled forward to carry your legacy within her body...

Within the hidden dimension of the Infinity Castle, where the very walls seem to breathe… a quickened breath now echoes.

Muzan lingered once more in her woman’s form. Pale as moonlight, with a curvaceous, mature body draped in dark robes that hinted at an ample bosom and generous hips. Eyes glowed a vivid, demonic crimson, and dark, wavy hair was tied into a gentle bun.

A gasp escaped Muzan’s red lips as you drew her closer once again…

A sharp-nailed finger rose to your pulse, a silent threat.

Muzan: “D-don’t dare… Stop this! You insufferable fool… I told you not to touch he—Mmmh!” Once again, the sharp hiss of her words dissolved into a stifled sound as she shut her eyes tight.

Her immortal, curvaceous figure pressed closer, yearning for more.

His true male form was forgotten. For months now, she had remained this way, in this female shape… just for you. And perhaps, her heart had become a woman’s as well. Muzan simply could not resist you—your body, your strength, your size… and your length, which she, in this form, could never forget.