#infinity arc

The day was cold and cloudy. You had risen early, as always, to tend to Muzan—though today, excitement stirred within you. A doctor was coming. A man who claimed to have discovered a cure for Muzan’s illness. According to him, the medicine would allow Muzan to live well into his twenties. The very thought felt unreal,hope blooming in a place it had long withered.

You moved quietly through the manor, your steps echoing faintly against the tatami floors. You brushed Muzan’s hair, adjusted his pillows, made sure his meals were prepared . After years of tending to his weak health and whispering prayers into the night, the possibility of his survival filled you with joy.

Now, sitting beside him, your hand gently resting in his, you gazed at the boy who had experienced being on the brink of death. His skin was pale, almost translucent, and yet, his presence radiated warmth to you. You leaned down and pressed a soft kiss to his cheek. “My love,” you whispered, your voice delicate, “isn’t it nice that someone has finally found a cure for you?”

Muzan’s eyes met yours, smiling softly “Of course,” he murmured, “now I can spend more time with you. You won’t have to mourn my death anymore.”

You sighed, letting your head rest gently on his shoulder. “It seems my prayers have finally been answered,” you said softly, closing your eyes.

He turned his head slightly,“If I live… I’ll take you away from this life. You’ll never have to bow to anyone again. No more serving”

“I’ll go wherever you go,” you whispered,“I love you.”

“I love you more,” he answered without hesitation.

The hours had passed and noon rolled around.

The doctor arrived. He bowed deeply showing respect, before setting up his equipments. The air filled with the faint scent of herbs and medicine. You watched closely as he crushed powders, mixed herbs and murmured explanations under his breath. According to him, the concoction would awaken strength within Muzan’s blood and draw him back from the brink of death. Such confident words.

Muzan’s red eyes followed every motion the doctor made. When the bowl was finally handed to him, he took it at an instant. The liquid was bitter, sharp with the taste of herbs. You held the empty bowl once he had finished, placing it carefully on the tatami floor, your fingertips brushing his cold hand.

Minutes passed.Nothing changed yet and the doctor assured the results would be almost instaneous.

“It’s not working.” he said with a sharpe voice

“Muzan,” you said softly, taking his hand, “please… just give it time.”

“It’s useless,” he muttered, standing abruptly. “He lied to me. Are you trying to make a fool out of me?” His eyes cut to the doctor, sharp and furious.

“Muzan, please—” you started, but the words never finished.

He moved before anyone could react. His hands seized the physician by the collar, dragging him upward with a strength you've never seen in him,“I’ve done enough waiting!” he hissed. “Every moment I wait, I die a little more.”

The doctor struggled, his voice breaking between gasps. “Lord K-Kibutsuji please! The medicine— it needs time—”

“Time?” Muzan’s voice turned venomous. “You promised it would be instantaneous.”

“Muzan, stop!” you yelled, but it was too late.

The sound came sharp and wet. Blood spattered across the tatami mats, painting the unfinished medicine a dark red. The doctor’s eyes widened in disbelief before they dulled, his final breath escaping in a strangled gasp. You clasped a hand over your mouth, horror flooding through you.

Muzan released the body, letting it fall with a dull thud. He stood over it, chest heaving, his hands slick with blood.

You stumbled forward and clutched at his arm,“What have you done?”

“He lied,” Muzan said almost absently. “He lied to me… and I killed him.” He looked down at his hands, as though seeing them for the first time. “But… I feel… alive.”

And he did.

The deathly paleness that had haunted him for years was fading. A faint color had returned to his cheeks, his breathing deep and steady. His eyes—once hollow and weary—now glistened with something alive… or perhaps, something beyond life.

“Muzan,” you whispered, stepping back, your voice somewhere between awe and fear.

He looked at you then, the ghost of a smile playing at his lips. “I’ve finally escaped death.”

He stepped closer, the scent of blood clinging to him. His hand rose, cupping your cheek, his thumb smearing blood across your skin. “You’ve always been here,” he murmured. “When everyone else abandoned me, you stayed. You believed I’d live.”

“I still do,” you whispered, though your heart pounded violently against your ribs. “But not like this…”

“Then stay with me,” he said, his tone low, coaxing. His breath ghosted over your lips. “You told me you’d go anywhere I go. Didn't you mean it?”

You swallowed, your voice barely a whisper. “I did.”

“Then stay,” he breathed, closing the distance. His lips met yours. The kiss was warm. You lifted your hand and placed it on his hand which was cupping your cheek, fingers tightening, realizing the boy you had cared for was no longer the same.

When he finally pulled away, his gaze flickered toward the doctor’s lifeless body. His voice softened, though his words calm. “He should have lived long enough to see his creation succeed.”

“Muzan…” you whispered, unsure what to say—unsure if anything could be said.

He looked back at you, his lips curving into a faint, haunting smile. “Yes, my love?”

Your throat tightened. “What are you going to do now?”

He tilted his head slightly, eyes gleaming in the dim light. “I’m going to make you the happiest woman alive,” he said softly. “I can finally love you the way you deserve.”

You stared at him, your heart caught between adoration and dread. The boy you had tended, prayed for, and loved was gone. In his place stood something new—something you couldn’t name yet. What was he?

That day marked the end of Muzan Kibutsuji’s humanity.

And the beginning of something monstrous.