Muzan returned to his spiritual core. His form was faint, his entire body becoming transparent.
Driven by a desperate will to live, he slammed himself again and again against the invisible walls around him. Behind him, a figure of black mist slowly took shape.
"You shouldn't have said that…" The voice carried no emotion, flat and mechanical.
Muzan froze. He didn't dare turn around.
The shadow walked closer, and with each step, the black mist faded from its head. At last its true face appeared.
It was… the same as his. The same face, the same features—yet the eyes were empty, lifeless, like a puppet with no soul.
The shadow raised its hand.
"Goodbye, Demon King… Kibutsuji Muzan."
The hand passed through Muzan's body. His form shattered like smoke. His expression twisted in terror, then froze, before he dissolved into nothingness.
Tsugikuni Residence
Though Yuichiro Tsugikuni's mansion was large, its rooms were almost bare. Only his own chamber held a few modest furnishings, and even that looked sparse.
"…Ugh. Why do I feel so uncomfortable?"
In the dream, I tried to move my body, but something bound me tightly.
Everything was pitch black. I couldn't see even my hand in front of me, yet my awareness was sharp. It made me feel strangely empty, as though I'd lost part of myself.
Then a shiver ran through me. My eyes snapped open.
Darkness. Heat. A face—so close I could feel the breath. Red eyes glimmered in the dark.
"…A gh-ghost!!"
I screamed, my voice breaking, forgetting completely that I myself was already a ghost.
After a long minute of frantic shouting and hurried explanation…
I leaned against the wall with a deep sigh, glaring at the one in front of me.
"So… you dragged me into your house because you were afraid I'd escape?"
Yuichiro sat in front of me, head lowered, one hand holding a book, the other pressing firmly against my abdomen to check the ropes. He didn't even look up as he replied flatly:
"…Yes. That's why I tied you up."
"What?! Are you kidding me?!" I thrashed in the bindings. "At least just tie my hands and feet! Who ties someone up like this?! Who even taught you this kind of—ugh! Tying up a girl like this?!"
Yuichiro ignored my protests, calmly tightening a knot. He studied the book in his hand, compared it, then nodded with certainty.
Finally, he turned the cover toward me.
The title read: "108 Binding Methods: All Tested, All Approved."
I froze. My eyes widened.
"…Wait… this… I… I wrote that…"
Memories flickered back. I had written it once. But I remembered giving it to Lady Tamayo…
Yuichiro muttered, deadpan. "…It's useful."
My face burned with shame. I lowered my head, too humiliated to respond.
"…You're abnormal…" I muttered at last.
The Demon Slayer Corps Mansion
Kagaya Ubuyashiki, too weak to stand, sat upright on his bed. His thin body shook with coughs before he composed himself. He turned his calm eyes toward the kneeling Flame Hashira.
"So that is what happened… Kyojuro?"
Rengoku raised his head. His expression was as bright and steady as ever, though his voice was hoarse, softened by the damage to his throat.
"Everything I reported is the truth!"
But it wasn't the full truth. He told the Master that the demon on the Mugen Train had been one of the Lower Moons, and that he had slain it without casualties. He made no mention of Kibutsuji Muzan's appearance—because he had promised Yuichiro Tsugikuni he would keep silent.
"Is that so…?" Kagaya smiled faintly, his eyes closing with relief. "Then perhaps this mission was indeed a success."
But then he paused, opening his eyes again.
"…Rengoku. That demon's Blood Demon Art controlled dreams, yes? Then how…" Kagaya's gaze lingered subtly on Kyojuro's throat. "…did it cause damage to your internal organs?"
Even ill, even weakened, the Master's insight cut deep.
Kyojuro's smile never wavered. "When I stopped the train, I was too close to the engine. The collapsing head of the locomotive released shockwaves… they struck me then."
It wasn't a lie. When he had unleashed Flame Tiger to destroy the engine, the explosion had shaken his insides. The damage was minor, but enough to explain the strain in his voice.
At least this way… he wasn't deceiving the Master.
At least, not completely.
From here on, I'm pretty satisfied with how the Mugen Train arc turned out. Kyojuro actually survived, though… it really messed up "Third Brother's" sales.
But some strange things happened too. Muzan's consciousness suddenly appeared—I nearly died…
Even worse, this emptiness in my chest, this strange anxiety, it's been getting stronger for no reason.
Still… maybe that's not important. What matters is, right now… I'm scared of Yoriichi Tsugikuni. Everything else feels unnecessary.
Butterfly Mansion
"Hmm… physically, he looks fine. But his eyes are unusual," Kanae Kocho tilted her head, studying me carefully. "Blood-red pupils, vertical cracks running through them…"
At this point, my body wasn't restrained, but my hands were bound. The rope in Yoriichi Tsugikuni's hand kept me in place as he led me to be examined by Kanae.
"For a human… or a demon, those eyes are indeed rare," Yoriichi nodded.
Hearing that, I glared at him sideways and moved my lips without sound. Of course, it wasn't in Japanese.
Yoriichi didn't try to figure it out. His gaze shifted down, looking at my worn clothes. My white shirt was ripped and filthy, like I'd rolled in the dirt. A thin blanket draped across my shoulders, barely covering the exposed tears.
Kanae scribbled notes quickly on a sheet of paper. I tried to peek, but she folded it before I could catch a single word.
"Well then," Kanae smiled softly, "from my observation, Mr. Fangō doesn't show any signs of mental illness."
"?!" I shot up from the stool. A thousand words ran through my head, but I clenched my teeth and held them back.
"Yoriichi Tsugikuni! You thought I was insane, didn't you?!"
Yoriichi immediately leaned in, his voice urgent. "No… I was just worried—"
"Worried about your sister!" I cut him off, fire in my chest. "A Demon Slayer worrying about a demon? If anyone else heard that, they'd laugh themselves sick!"
I wanted to pummel him. Just because Muzan's lingering will appeared, and I passed out for three days… you think that means I've lost my mind?
We locked eyes. Neither of us spoke, neither could back down. The tension froze us in place.
…In the end, I just clapped my hands, turned away, and walked out of Kanae's clinic. My anger cooled a little, though one of my wrists was still tied by that rope.
Yoriichi followed quietly. His cheeks were a bit red, and there was this faint, almost foolish smile tugging at his lips. Like he'd been struck but was oddly… happy about it.
Kanae stayed behind, thoughtful. "Yoriichi Tsugikuni… the swordsman who became a Hashira the moment he appeared before Oyakata-sama. His origins unknown, his breathing style seemingly the very first. And yet…"
Her gaze lingered on the memory of what she'd seen: Yoriichi, a man as unshakable as stone, had been slapped dozens of times by a demon. Not with force, but with ridiculous speed. And he had smiled.
"That man… to be hit by a demon whose allegiance is uncertain, and to not be angry, but to smile?" Kanae whispered.
Of course, Yoriichi was wrong to suspect someone's sanity without proof. But being happy after being beaten? That was far stranger.
"…Master Yoriichi, the man with the wooden face, smiling after a demon slapped him…"
Kanae shook her head, troubled. Such closeness between a Hashira and a demon—what would people say if they knew?
She brushed off the thought. There was work to do. Medicines to prepare, poisons to refine, injured members waiting for treatment. Still, as she reached to touch her own left shoulder, her expression dimmed.
"…Special pupils…?" she murmured.
Across the room, a spotless Corps uniform hung neatly. But a hole pierced through the left shoulder, cutting straight through the fabric.
Kanae pulled a golden button from her desk drawer, staring at it quietly. Her fingers tightened.
"…Shinobu… whatever you do, don't cross paths with him."