In the Butterfly Estate, when they learned that Tomioka Giyu was missing, his life or death uncertain,
Tanjiro's eyes filled with sorrow and pain.
"How could that be? Giyu is so strong… Even if the opponent was an Upper Rank…"
Zenitsu wanted to say something to comfort him, but after hesitating for a long time, he couldn't find the right words.
Based on what they'd heard, Zenitsu no longer had much hope.
Instead, Inosuke confidently slung an arm around both of their shoulders and bellowed,
"Hey! What are you two mumbling about?!"
"Don't you know how strong Giyu is?! He's gonna be fine!"
"As for what that scarred monster said, it's gotta be a lie!"
Honestly, it was a blessing Sanemi Shinazugawa wasn't present—Inosuke would've definitely been knocked flat by now.
Meanwhile, upon hearing the news, Ubuyashiki Kagaya immediately dispatched more Kakushi to search the surrounding forests.
The Master of the Demon Slayer Corps had a strong feeling—Tomioka Giyu was not dead.
Later that afternoon, in the Butterfly Estate, Kocho Shinobu finally woke up in a daze.
She stared blankly at the ceiling. How she wished this was just a dream.
The door creaked open, and Kanae Kocho entered with a tray of food.
"Shinobu?! You're finally awake. You must be starving," Kanae said gently. "Come on, I brought your favorite."
Shinobu sat up and shook her head softly. "I don't want this, Sister. I want radish salmon."
Kanae was stunned at first—but quickly understood her sister's meaning.
"…Alright, Shinobu. Just wait here. I'll go buy it for you right away."
"Thank you, Sister."
Shinobu took the salmon plush from the bedside table and held it tightly, her mind elsewhere.
But where exactly was Tomioka Giyu?
In a pure white void, Giyu slowly woke, his mind still dulled.
But within moments, he stood up and looked around. There was no pain in his body.
"Am I dead…? Is this heaven?"
"…Well, at least I'm not a burden to the Demon Slayer Corps anymore," he muttered.
"But still… it's hard to accept…"
Just then, a very familiar voice called out to him.
"You died a little too early. I thought you'd show up when we reached the Infinity Castle."
Giyu turned toward the voice—only to see a face exactly like his own.
"Huh? You? No… That's not right… It's me?"
Yes, the one who had spoken was none other than Qin Zi—no, it was Giyu's own soul.
Having read many stories and trained his perception, Giyu understood quickly.
"…I thought you—we…"
Qin Zi (Tomioka's soul) remained calm. "Enough. Let me explain. Just listen."
And so Giyu listened.
After about ten minutes, it was clear: When Qin Zi had become Giyu, Giyu had become Qin Zi. Their souls had swapped across time.
Giyu was stunned.
"Wait… That means I'm your descendant?!"
"And because of your regrets and willpower… our souls traded places?"
Qin Zi nodded. "Seems like it."
Giyu stood in stunned silence. Then, after a while, he spoke softly.
"…So, how's my life been for you? Pretty boring, huh?"
But Qin Zi just gave a rare smile and replied:
"No. I love this life. What you find painful—I yearn for."
Giyu had no reply.
Qin Zi raised two fingers.
"Alright. You can't waste time here. If you want to go back, you need to choose."
"Either defeat a mirror image of yourself…"
"…or kill me."
Giyu smiled wryly. "You know I can't do either."
"No matter how you look at it, it's not possible."
"You said it yourself—we're the same person. How could I kill myself?"
As he said this, a mirror image of Tomioka Giyu manifested in the white space.
"Go on. Take care of my sister, and our parents. I Don't want to worry about them anymore."
"Protect everyone in the Corps." Qin Zi said in response.
"Be careful—if you die next time, it'll be for real." He continued.
"I'll give you one clue: if you can't break through, you won't defeat yourself."
And with that, Qin Zi—Tomioka's soul—vanished.
What Giyu would never know was that Qin Zi had used every ounce of swordsmanship and every memory of Demon Slayer to create this opportunity.
From now on, he would be just an ordinary man. A real Qin Zi, living a peaceful life.
A Nichirin Blade appeared in Giyu's hand.
He didn't strike right away.
Instead, he offered silent thanks to Qin Zi in his heart.
Even though he had considered his past life dull, his family had always been the one thing he couldn't let go of.
And now that he knew the truth, he could finally set down that heavy stone in his heart.
"…I must break through."
He rolled his shoulders, gripped his sword tightly—and struck!
A blade flashed toward the neck of his mirrored self—
—but the mirror Giyu overlapped with his movement, expression blank.
"Water Breathing: Thirteenth Form — Marked State: Mirror Flower, Water Moon."
The mirrored blade slashed down.
But Giyu, too, split into afterimages.
"You think I wouldn't know that too?!"
Of course, this mirror opponent was Tomioka Giyu.
They moved in unison, perfectly matched, each testing the other with feints and technique.
Countless forms exchanged—yet neither could land the final blow.
And eventually…
…the time limit on the Thirteenth Form ran out.
***
Bang—
No one knew how long it had taken, but Tomioka Giyu now lay exhausted in the vast, pure white void, muttering under his breath:
"…It's the same technique. There really is no way to break it…"
"Tch. I need to get out of here quickly. Looks like I'll have to focus completely on developing a new form."
"For now, I'll set aside the Transparent World."
While Giyu was immersed in creating a new sword form, elsewhere, the Hidden Corps had no choice but to withdraw after days of fruitless searching.
Each Hashira had duties they couldn't abandon, no matter how anxious they were.
Only Kocho Shinobu remained unwilling to give up.
She had to see Giyu again—dead or alive.
She would never rest otherwise.
Back in the white space, Tomioka Giyu gradually calmed himself.
Relying on his deepened understanding of water pressure gained from the Fourteenth Form, Abyssal Sea, his new technique soon began to take shape.
His Nichirin Blade shimmered with a continuous light-blue glow.
"…It's time to end this."
With a brilliant flash of blue, the mirror image's blade shattered—and Giyu cleaved through his other self's neck with a single clean strike.
"Hmph. Just as I suspected… water pressure can cling to the blade indefinitely."
"But if I'm to call this the Fifteenth Form, it needs serious refinement. At the very least… it should be able to emit ranged sword energy."
As Giyu muttered to himself, a glowing blue door appeared before him.
He didn't hesitate.
Opening the door, he stepped through.
A blinding white light engulfed him.
When he opened his eyes again—
He was lying in the forest, right where he had once stabbed his own heart.
"…Huh?"
Looking down at his bloodstained uniform and the trampled grass beneath him, Giyu muttered in disbelief.
"…I'm back?"
His eyes scanned the area.
"…Where's my sword?"
He searched the ground, but there was no trace of the Nichirin Blade.
"If the Demon Slayer Corps recovered it, that's fine… But if it was picked up by someone else…"
Rustle.
The faint sound of footsteps in the forest behind him made Giyu spin around warily.
It was night, and a dreadful possibility flashed across his mind—
Could Kokushibo have returned?!
(Bro got ptsd now 🥀)
But when he saw who emerged from the trees, Giyu froze.
And the person who stepped out also stopped in her tracks.
Giyu's lips curved upward slightly. He lifted a hand and waved.
"I told you I'd be fine… I'm back, Shinobu."
The figure before him was none other than a pale, disheveled Kocho Shinobu—nearly collapsing from exhaustion.
She didn't answer. Instead, she smiled quietly, almost mockingly.
"…It's just another illusion again. Still… it's nice to see you, you bastard."
The words pierced Giyu's chest like a knife.
He took two quick steps forward and pulled her into his arms.
Shinobu didn't resist.
For a moment she just stood there, stunned.
Then, her voice trembled.
"…Is it really you?"
"…Not an illusion…?"
Giyu met her gaze, his own eyes steady and solemn.
"It's me, Shinobu. I'm sorry… for making you worry."
At that, Shinobu burst into tears, pounding her fists weakly against his chest.
"Wahhh! You bastard! I thought… I thought you'd really left me forever!"
"Do you know how scared I was?! You still owe me dinner—don't think you can die and skip out on that!"
"You're not allowed to die! Ever again!"
Her fists trembled as she clung tightly to his neck, as if afraid he'd vanish again.
Giyu's vision blurred with emotion. His heart swelled with both grief and joy.
"…Idiot. You think I can control whether I live or die?"
"I don't care!" she shouted, pulling back with a stubborn pout. "You just can't die!"
"If you do… I'll like someone else instead!"
The threat was so childish and desperate, it nearly made Giyu laugh out loud.
"…Oh?"
He caught her small hand in his own.
With the other, he gently lifted her chin.
And then—he kissed her.
Eyes wide with confusion, Shinobu instinctively resisted.
But when Giyu leaned deeper into the kiss, she closed her eyes… and melted into his arms.
Much later, Giyu finally let her go.
Shinobu, nearly out of breath, leaned heavily against him.
He gently wiped the corner of her mouth—she hadn't had much energy to start with.
"Now… are you still planning to like someone else?"
Shinobu gave him a dazed, teary look.
"…That was just to scare you. I only like you…"
Her cheeks turned crimson.
Then, with flushed determination, she stared at his lips again and whispered:
"I want to kiss you again…"
There was no way Giyu could refuse her like this.
After the second kiss, Shinobu was truly out of strength.
She clung to him like a sloth, her head resting on his chest.
"…I'm out of energy, Giyu… Can you carry me back?"
Before Shinobu could panic, he scooped her up in a gentle princess carry.
"I'm taking you home, silly girl."
Shinobu rested her cheek against his chest, listening to the steady beat of his heart.
"…Idiot," she whispered softly.
On the way back, all the tension and grief she'd been holding in finally released.
After so many sleepless nights, finally reunited with him, her body relaxed completely in his arms.
Soon, she was fast asleep.
Her expression—usually stern or wry—was now peaceful, even happy.
Giyu moved carefully, making sure not to jostle her or disturb her rest.
Nearly an hour later, he arrived at the Butterfly Estate.
In the courtyard, Kocho Kanae sat on a bench, worry written all over her face.
She'd clearly been waiting for her sister's return.
Beside her, Kanao sat quietly.
She was the first to spot them—and for once, a spark of emotion lit up her calm expression.
Giyu quickly raised a finger to his lips and made a shh gesture.
Kanao understood instantly.
When Kanae turned around, her eyes lit up in shock—but before she could shout in joy, Kanao gently covered her mouth.
She pressed her index finger to her own lips and shook her head slowly, signaling Kanae to keep quiet.