Chapter Text
Prologue: Muichiro’s Final Moments
The air in the Infinity Castle was thick with darkness, its labyrinthine corridors echoing with distant clashes of battle. Amidst the chaos, Tokito Muichiro lay on the cold ground, his body broken and bloodied from the relentless fight against Kokushibo, the Upper Moon One. The fight had been brutal, a clash of wills that ended with the demon’s destruction—but at a devastating cost.
Muichiro’s breaths were shallow, each one a struggle against the inevitable. Pain lanced through him with every movement, but his thoughts were elsewhere. His vision blurred, and the oppressive darkness around him seemed to melt into memories—fragments of a life that now felt distant.
He thought of his twin brother, Yuichiro, the one he had loved and lost. Their bond, once strained and then severed, weighed heavily on his heart even now.
“I’m sorry, Yuichiro,” Muichiro murmured, his voice barely a whisper. “I understand now. You were always trying to protect me… even when I couldn’t see it. I hope you’ll forgive me… for being so blind.”
As his vision faded further, other faces flickered in his mind
—Oyakata-sama, Kagaya Ubuyashiki, who had saved him from his despair and given him purpose; the Hashira, his comrades in this harrowing fight against evil
—the Hashira, his comrades who had become like a family. Gyomei’s calm guidance, Mitsuri’s warmth, Shinobu’s sharp but caring demeanor, and even Sanemi’s fierce loyalty—they were all vivid in his heart. Obanai came to mind too, his quiet intensity and the ever-present snake coiled around him. Muichiro had often found Obanai’s reserved nature to be a reflection of his own, though the older Hashira’s sharp words sometimes carried a weight of wisdom. He had fought alongside them, laughed with them in rare moments of peace, and now he felt a pang of regret that he wouldn’t see them again.
— the Flame Hashira, Rengoku Kyojuro, standing tall with his usual bright and unwavering smile.“Tokito,” Rengoku’s voice resonated, strong and filled with kindness. “You’ve done well. You’ve fought bravely and protected so many. I’m proud of you.” Muichiro suddenly remembered the day he had first become a Hashira, still a boy of just eleven. While many had been skeptical of his promotion due to his age and aloof demeanor, Rengoku had been the first to speak up for him.“ An incredible talent,” Rengoku had declared at the Hashira meeting, his voice booming with enthusiasm. “You have earned your place among us, Tokito. Age does not diminish your strength or your heart!” Rengoku had patted Muichiro’s head then, his gesture gentle yet filled with the warmth of an older brother.
—Kamado Tanjiro.
Before Muichiro could allow himself to reflect on the boy who had reminded him of his humanity, another thought crept in—a lingering worry, one that gnawed at him with increasing intensity.
Is Tanjiro still alive?
His heart sank at the mere thought. Tanjiro, so strong, so determined, but still just a boy—a boy who had been through so much. Muichiro’s own death felt inevitable now, but he couldn’t shake the desperate hope that Tanjiro, the kind-hearted boy who had reminded him of his own lost innocence, had survived.
Has he made it through?
Muichiro's mind raced. He had watched Tanjiro fight with everything he had, driven by a love for his sister Nezuko, for his friends, and for a future that seemed so far away. Muichiro knew Tanjiro’s strength, but even still, he couldn’t bear the thought of him falling, of him fighting alone against the overwhelming darkness.
I wanted to protect you, Tanjiro… Muichiro thought, his chest tightening with helplessness. I wanted to keep my promise, to stay by your side…
But now, his body was failing him. The weight of his injuries pressed down on him like a crushing force, and Muichiro realized, with great sorrow, that he couldn’t protect Tanjiro anymore. No matter how hard he tried, no matter how much strength he summoned, he had reached the end.
His breath hitched in his throat as he came to terms with the truth. I can’t help you anymore, Tanjiro. I won’t be there to guard your back… I won’t be able to help you defeat Muzan. But you must survive. You must. You’ve come this far. You deserve to reunite with Nezuko. You deserve to live the life that’s been stolen from you. Please… survive this battle.
Muichiro’s heart ached with the desire to do more for Tanjiro, to be there for him, to see him through the final battle. Please, Tanjiro, hold on. You can do it. You have to. You’re strong. You’ve always been strong.
But he couldn’t protect him anymore, and the acceptance of that loss weighed heavily on his soul. He had to let go.
As the pain in his chest grew heavier, Muichiro thought of the promises they had made—the promise to Kotetsu, the boy he had once protected, and the promise he had made to himself. He had wanted to spend more time with him, to get to know him better. Tanjiro had become someone important to him—perhaps even the closest thing to a brother he could have had. But there had never been enough time. Muichiro wondered, fleetingly, if they could have been best friends, or even like siblings, had things been different. I wanted to try, he thought, a pang of regret tightening in his chest. But now, those promises seemed to hang in the air, unfinished.
The reality of his death was undeniable. His final moment had come, and with it, the bitter realization that he wouldn’t be able to see the end of this war.
And yet, as his mind and body began to shut down, Muichiro clung to one final wish. Please, Tanjiro. Live. Fight. Survive. You deserve it.
A sudden, unexpected sound broke through the haze of his thoughts—something familiar, something comforting. It was the fluttering of wings. Weakly, Muichiro turned his head toward the sound and saw Ginko, his faithful crow, perched nearby.
“Ginko…” Muichiro whispered, a faint smile tugging at the corner of his lips. “You remembered our promise… didn’t you?”
The crow’s dark eyes shimmered with sorrow as she cawed softly, her small body trembling.
“Ginko,” Muichiro murmured, his voice growing fainter, “do you remember? The promise we made… long ago. No matter what happens… you must do your duty. Inform everyone about my death. Then… then you have to fly away.”
Ginko looked at him, unwilling to leave, but Muichiro knew what had to be done. She had to carry on, no matter how much it hurt.
“You promised me,” Muichiro urged. “Please. You have to tell them… then help Oyakata-sama. Help him finish what we started.”
He knew it was too much to ask of her. But he had no choice.
“Thank you,” Muichiro whispered, his final thoughts turning to the bonds he’d shared with others—his comrades, his family, his friends—and especially Tanjiro.
And just as his strength was beginning to wane, a voice broke through the darkness, steady and reassuring.
“Muichiro,” said Himejima Gyomei, the great stone Hashira, his voice filled with reverence. “You did well. Because of you, Kokushibo is no more. You were crucial in his defeat.”
Muichiro felt a deep sense of peace wash over him at those words. It wasn’t for nothing…
“We will destroy Muzan,” Gyomei continued, his voice unwavering. “For your sake. Rest now, Muichiro. You’ve earned it. Your sacrifice will not be forgotten.”
Muichiro’s chest tightened, not with pain, but with relief. He had done all he could. His comrades would carry on the fight. They would defeat Muzan.
And then, as if the universe itself had orchestrated it, another presence filled his fading vision. The face he had long forgotten, yet now realized he had desperately longed to see.
Yuichiro.
At first, it was unclear—just a vague shape, a faint outline—but as the image sharpened, Muichiro could no longer deny the truth. It was his twin brother.
“Yuichiro…” Muichiro whispered, tears gathering in his eyes. His regret, the sorrow he’d carried for so many years, flooded his heart. I’m so sorry… for everything…
His twin brother’s face was soft, filled with understanding. The anger, the resentment, all the distance between them seemed to vanish in that one moment. Yuichiro’s face was full of compassion, forgiveness—the very things Muichiro had needed, but never thought he would get.
“I’m sorry…” Muichiro’s voice faltered as his twin’s face loomed closer. “For everything, Yuichiro. For not being there. For the fight… I should have never left you. Please forgive me.”
Yuichiro didn’t speak—he didn’t need to. His face was all the forgiveness Muichiro needed. The weight of his brother’s spirit was enough to ease Muichiro’s heart.
And as the last of his strength faded, Muichiro finally smiled, knowing his twin had forgiven him. The words he never got to say, the apology he never thought he would make—he had finally found peace.
In that final moment, Muichiro could rest, knowing that his comrades would carry on his legacy. That Tanjiro would live, and the world would one day be free of the demons that had ravaged it for so long.