Tanjiro walked along the forest path, following his kasugai crow's directions with several demon slayers trailing behind him. He had just finished sword-technique correction under the Snake Hashira, Iguro Obanai. The Hashira Training was brutal, extremely tough, painful, and exhausting, but Tanjiro knew he was growing stronger with each round.
And now… the next training camp awaited him.
Akira's camp.
Tanjiro felt a flicker of excitement. Akira was overwhelmingly strong, unbelievably smart, and whenever Tanjiro trained with him, he felt himself leap forward by entire steps instead of inches. So despite the exhaustion weighing on his shoulders, he actually found himself looking forward to the next round.
But then.
As Tanjiro followed the path into a small clearing, he froze.
There was a cart sitting there.
And in that cart sat… Panchan.
Except that Panchan was wearing a frilly dress that looked like it belonged to a foreign princess. Tanjiro sniffed out of habit and blinked. There was no scent of Akira coming from it. It really was just… a doll?
But that wasn't the strangest part.
What caught Tanjiro's attention far more were the bodies scattered across the ground around the cart. Demon slayers lay sprawled out like fallen soldiers after a war. Some twitched. Some groaned. All looked like they had seen true despair.
Among them was someone he knew.
"Zenitsu!?"
Tanjiro rushed to his friend, dropping to his knees in panic.
"Zenitsu! Get up, what happened to everyone!?"
Zenitsu, looking like he had already lived through the afterlife and come back, grabbed Tanjiro's sleeve weakly.
"Ta–Tanjiro… run… while you still can… before it begins again…"
"Before what begins!?"
But before Zenitsu could elaborate.
KAAA! KAAA!
Two Kasugai crows swooped overhead. Tanjiro recognized them immediately.
Raven and Rose.
Akira and Erika's crows.
Raven screeched,
"Kaaa! Kaaa! Break time over! Break time over!"
Rose followed elegantly,
"Prepare for the next round. Prepare for the next round."
All the "dead bodies" on the ground let out groans of despair.
Some cried openly.
Others whimpered.
But despite the misery, they forced themselves shakily to their feet.
Tanjiro stared, horrified.
"What… what is happening?"
Zenitsu grabbed him by the collar, shaking him with tears in his eyes. "It's about to begin again, Tanjiro!!" he wailed miserably.
As Tanjiro stood there, bewildered, the crows fluttered down to perch atop the princess-dressed Panchan. Rose cleared her throat delicately, if a crow could do such a thing and spoke in her refined, melodic voice.
"Since new participants have joined us," she began gracefully,
"I shall now explain the rules once more."
Tanjiro blinked. Rules? For what?
Rose spread her wings dramatically.
"You must transport the cart…" she gestured with a wing toward the princess Panchan, "through the forest and reach the opposite side. The forest is filled with traps. You must navigate all of them."
Tanjiro swallowed. "Traps?"
Zenitsu already looked like he wanted to collapse again.
"And most importantly," Rose continued with serene elegance, "A monster will attack during the final stretch. You are not required to defeat it, only to escort Princess Pinky-chan safely to the finish line."
"Princess… Pinky-chan?" Tanjiro stared at the Panchan doll in its ridiculous princess dress. "This was Princess Pinky-chan?"
Raven flapped above them. "KAAA! Training begins in sixty seconds! Sixty seconds! Prepare yourselves!"
A chorus of despairing cries rose from the exhausted demon slayers around Tanjiro. But even while sobbing, groaning, or mumbling about their impending doom, every single one forced themselves to stand and get ready.
Zenitsu clutched Tanjiro's sleeve, trembling.
"I–I can't even run anymore, Tanjiro! If I collapse again, Akira-san will turn me into a test subject! I know it! I know it!"
He was crying so hard his voice cracked.
Tanjiro, completely lost but determined, tightened his grip on his sword.
"Even if I don't understand… I still have to give it my all!"
Under Raven's countdown, the demon slayers quickly organized themselves.
Some volunteered, reluctantly to drag the cart.
Others formed a guard around it.
And then.
They began the march into the forest, dragging Princess Pinky-chan behind them as though escorting royalty through a battlefield.
They made it only a few steps before Tanjiro noticed something.
Tanjiro suddenly stiffened. His nose twitched.
"Wait…don't step on…!"
Too late.
A demon slayer's foot pressed down on a concealed mechanism, and PFFFT!!
A burst of pink smoke exploded upward like a cheerful festival firework.
The demon slayer blinked, unharmed.
"Oh… I think I'm fine?" he sighed in relief, still clueless.
Zenitsu's scream tore through the forest.
"NOOO!! NOT THE PINK ONE!! COVER YOUR NOSES! DON'T BREATHE IT IN!!"
Tanjiro whipped around.
"Zenitsu! What is it?!"
But then.
The affected slayer chuckled.
"Heh… hehe… guys? Nothing happened, I'm fi…HAHAHAHA!"
His voice broke into a cackle.
Then another.
Then uncontrollable, full-body hysterics.
"G…GUYS…HAHAHAHA…I CAN'T…STOP…HAHAHAHA…!!"
Tanjiro stared, horrified.
"What is happening to him?!"
Zenitsu grabbed Tanjiro by the collar, eyes full of trauma.
"It's laughing gas! He calls it 'Jocker Gas'! It makes you laugh for an hour! An HOUR!"
"An hour!?"
"It used to be a whole day, but Erika-san said that was too cruel…only after she scolded him he reduced the effects."
Tanjiro stared, dumbfounded. he felt a chill run through him.
With no way to help the poor laughing victim, the group pushed forward, dragging him along while he wheezed and cackled like a dying hyena.
Tanjiro decided to rely on his sense of smell to detect traps, but halfway through a cautious step.
"Heh…ACHOO!!"
Something stung his nose, and suddenly everything went blank.
"My sense of smell… it's gone! I can't smell anything!"
Zenitsu nodded with the dead eyes of a man who had lived through many tragedies.
"Yeah… that's him. At first I used my hearing to guide everyone, but suddenly all sound disappeared for me. Something in the air temporarily shuts off your senses."
Tanjiro paled.
"Is… is that even allowed…?"
"Apparently not," Zenitsu said dryly. "Erika-san scolded him for going too far, so now I can hear normally again. But your smell is probably gone until this is over."
Tanjiro groaned. "How do we move forward now…?"
Zenitsu patted his shoulder.
"Don't worry. After this let's complain to Erika-san together. He only listens to her."
Without Tanjiro's guidance, disaster descended quickly.
Another slayer stepped on a pink trap → unstoppable laughter.
One hit a yellow trap → instantly burst into sobs, wailing about the meaninglessness of life.
A red trap → violent nonstop sneezing.
A green trap → itching so severe he rolled on the ground begging for mercy.
Tanjiro stared, horrified.
"What… what is this hellish place…?"
Zenitsu trembled.
"This? This isn't even the worst part."
The forest echoed with:
Laughing.
Crying.
Sneezing.
Itching.
And Zenitsu's endless despair.
But somehow barely, painfully, they kept moving, dragging Princess Pinky-chan onward like a cursed royal escort.
High above the chaos, perched casually on a thick tree branch, Akira and Erika watched the struggling demon slayers stumble through the forest of chemical doom.
Akira grinned like a proud scientist watching his lab rats thrive.
"Oh, nice! See? All my new chemical formulas work perfectly."
Erika rubbed her forehead. "I still can't believe you're testing your experimental drugs on them."
"It's training!" Akira said defensively. "What if a demon uses effects like these someday? And besides, where else am I supposed to find this many test subjects?"
Erika let out a long, exhausted sigh. "I still can't believe everyone agreed to this."
"They didn't," Akira admitted. "But once I told them it would increase their resistance to status effects, they reluctantly accepted. Though I still don't get why they rejected the fear gas."
"Because that's too cruel, Akira." Erika muttered flatly.
Akira shrugged. "Anyway, it's our turn. We should get ready."
Akira gave a thoughtful shrug.
Erika looked down again. "Is it our time yet?"
"Seems like it," Akira said, stretching. "Let's get ready."
Erika sighed for the twentieth time that morning, wondering how she had let herself get dragged into this madness.
Just then, the exhausted demon slayers finally reached a wide clearing. The finish line was just beyond it, but standing before the final stretch was a massive water tank with a huge sign painted across it:
HEALING WATER
The moment the slayers from earlier rounds saw it, their eyes sparkled like they'd found salvation. Instantly, they rushed toward it, drinking eagerly.
Tanjiro glanced at the excited demon slayers crowding around the water tank, baffled.
"Why is everyone heading there instead of going straight to the goal?"
Zenitsu, who already looked spiritually broken, answered with the weary tone of a man who had lived this nightmare far too many times.
"That's the recovery water. If you drink it, you get all your strength back… and every single gas effect is cured."
Tanjiro brightened. "Really? Then shouldn't we just go to the goal and then drinking the water"
"No," Zenitsu said immediately. "We can't. The final trial is still here. Trying to escape it is pointless."
Tanjiro blinked. "Final trial? They said a monster is coming, what does that mean?"
Zenitsu shuddered dramatically. "You'll know… soon. But first, let's drink."
With no other choice, Tanjiro followed. The moment the healing water touched their lips, a wave of relief washed over the group. The laughter stopped. The crying stopped. The sneezing and itching vanished like they were never there in the first place.
Everyone straightened their backs, stretching, rolling their shoulders, marveling at how much better they felt.
It was peaceful.
Tanjiro wiped his mouth after drinking the recovery water.
"This is great," he said, genuinely relieved. "But… if they're going to attack us, why heal us first?"
Zenitsu looked like a man who had lived through too much.
"At first it didn't happen like this," he said, trembling at the memory. "Akira-san used to attack while the gas effects were still on us. But Erika-san scolded him, said it was too cruel and that nobody would grow stronger that way. So now he heals us before beating us."
Tanjiro opened his mouth to respond, but the forest shuddered.
A faint vibration trembled through the ground.
A new demon slayer stiffened. "S-Something's moving… in the forest. Something not human. What is that…?"
The veteran demon slayers immediately tensed, their expressions darkening with shared trauma.
"It's here," one muttered.
"Everyone, stay on guard." another warned.
Tanjiro felt his heartbeat quicken.
"What is it?" he whispered.
Zenitsu swallowed, dread twisting his face. "The monster."
As if waiting for that single declaration, the forest exploded.
Something shot out of the shadows, fast, heavy, and unnatural, landing between the demon slayers and the finishing point with a thunderous impact that rattled the ground.
Tanjiro's breath caught.
"W–What… is that?"