The Swamp Demons swore that if they were ever given another chance, they would listen to their instincts and never underestimate Demon Slayers again.
But unfortunately for them, regret came far too late.
Two hours earlier…
By the time Tanjiro and Inosuke arrived in the town, night had already fallen completely.
The streets were dimly lit by lanterns, the air damp with the smell of rain-soaked earth. Shadows stretched across the narrow roads, and somewhere in the distance, dogs barked uneasily.
Inosuke, however, was overflowing with excitement.
"Finally! Demons again!" he shouted while pounding his chest. "I'm gonna rip them apart!"
Hidden beneath the streets, the three Swamp Demons quietly observed the newcomers.
Unlike before, these demons had learned enough caution to distinguish one another during combat. Their names were Gan, Wen, and Cui.
Gan clicked his tongue while holding the hair ornament of one of the girls they had devoured.
"What's this? Two Demon Slayers this time?"
Wen snorted dismissively.
"They're just rookies. Three demons against two humans? We'll crush them."
Cui grinned wickedly.
"Let's drag them into the swamp immediately."
Without warning, the ground beneath the alleyways began to liquefy.
A dark swamp spread silently through the streets toward Tanjiro and Inosuke.
Tanjiro's sense of smell instantly reacted.
His expression sharpened.
"Something's coming! Inosuke, be careful!"
Before either of them could fully prepare, the swamp exploded upward.
Three demons burst from the mud simultaneously and landed against the walls like grotesque insects crawling from the darkness.
Moonlight illuminated their twisted faces.
For an instant, the atmosphere became suffocating.
Even Tanjiro and Inosuke paused slightly.
Only slightly.
Gan spread his arms arrogantly.
"So you're from the Demon Slayer Corps again? Too bad. Once you've stepped in here, you're not leaving alive."
The three demons lunged forward together.
But instead of retreating, Inosuke burst into laughter.
"Hahaha! Perfect timing!"
He instantly drew both Nichirin Blades.
Beast Breathing • Second Fang: Slice Apart!
The jagged twin swords crossed violently.
A savage slash exploded outward and sent Wen flying across the alley.
But at the same moment, Gan appeared before Inosuke with claws extended toward his throat.
Unfortunately for him
Tanjiro was already moving.
Water Breathing • First Form: Water Surface Slash!
A clean arc flashed through the darkness.
Gan's arm spun into the air before crashing onto the street.
The demon's scream echoed through the alley.
At that same moment, Cui and Wen attacked Tanjiro from opposite sides.
"Too slow, brat!" Cui snarled as his claws shot toward Tanjiro's back and toward the wooden box he carried.
His claws nearly touched the box.
Then
THUD!
A powerful kick smashed directly into Cui's face and sent his head spinning through the air.
Nezuko landed gracefully beside Tanjiro.
Her pink eyes burned with fury.
Wen froze briefly in shock.
"A demon?!"
Tanjiro also seemed surprised for a moment. He had not expected Nezuko to leap out on her own.
Meanwhile, Inosuke kicked Wen squarely in the stomach.
The impact launched the demon backward like a ragdoll.
"You think I'm not here?!" Inosuke roared.
Now the battlefield shifted completely.
Tanjiro, Inosuke, and Nezuko stood back-to-back in formation.
The three Swamp Demons suddenly felt something they had not experienced in a long time.
Pressure.
Real pressure.
Cui reattached his head while glaring viciously at Nezuko.
"What kind of nonsense is this?! Since when does the Demon Slayer Corps bring demons onto missions?!"
Tanjiro tightened his grip on his sword but did not rush recklessly.
This was his first official mission.
He still lacked experience.
Unfortunately for the demons, Inosuke lacked restraint instead.
"Hahaha! Stop sinking into the ground and fight me properly!"
He charged directly at Gan like a wild boar descending a mountain.
Gan hurriedly submerged into the swamp to dodge the attack.
Meanwhile, Tanjiro engaged Wen head-on.
Sword and claws collided repeatedly, sparks erupting with every strike.
At first Tanjiro had assumed these demons would be overwhelmingly powerful.
But after exchanging blows, he realized something.
They were not stronger than the demons from Final Selection.
On Nezuko's side, her combat style became increasingly fierce.
At first she tried punching Cui repeatedly.
But after missing several times, she switched entirely to kicks.
Her movements became sharper and faster, each kick carrying monstrous physical force.
Cui was battered backward continuously.
The three Swamp Demons finally realized the situation was turning disastrous.
"Retreat!" Gan shouted. "Split up!"
Their usual strategy was simple:
Three against one.
Overwhelm and devour.
But tonight
they had chosen the wrong opponents.
Inosuke suddenly joined Tanjiro against Wen.
Now the battle became:
Two against one.
And one against two.
Wen nearly lost his mind.
"You idiots!" he screamed toward the others. "Didn't I tell you to keep one of them busy?!"
Gan looked back briefly while dodging Nezuko's kick.
"You hold them off first! We'll kill the demon girl and then help you!"
Wen almost coughed blood from rage.
"HOW AM I SUPPOSED TO HOLD THEM OFF ALONE?!"
Tanjiro and Inosuke attacked together relentlessly.
Wen could barely survive.
Meanwhile, Nezuko was indeed stronger than Gan and Cui individually, but she still lacked combat experience.
Gan suddenly slashed his claws across Nezuko's forehead.
Blood splattered into the air.
Nezuko staggered briefly from the pain.
Cui seized the opening immediately and grabbed her by the throat.
"Nezuko!" Tanjiro shouted.
Instinctively, Tanjiro tried to rush toward her.
That moment of distraction gave Wen an opportunity.
"I've got you now!"
Wen shoved aside Inosuke's blade and slammed his forehead directly into Tanjiro's head.
CRACK!
The next moment
Wen collapsed to the ground clutching his skull.
"My head… why is his forehead so hard?!"
Even Inosuke paused in disbelief.
Then he immediately capitalized on the opening.
Beast Breathing • Fourth Fang: Slice 'n' Dice!
His jagged blades tore through Wen's neck.
The demon's head flew into the air.
At the same time, Gan and Cui prepared to finish Nezuko off.
Then
a thunderous sound erupted across the alley.
FWOOOSH!
Thunder flashed.
A streak of golden lightning cut through the battlefield instantly.
Thunder Breathing • First Form: Thunderclap and Flash • Sixfold!
Before anyone could react, Cui's arm and Nezuko herself had vanished from their original positions.
Zenitsu appeared several meters away while carrying Nezuko protectively in his arms.
His eyes remained shut.
But his expression was terrifyingly serious.
"How could you treat a girl like that…?" Zenitsu muttered in his sleep. "I won't forgive you."
Gan's face twisted in horror.
"What the hell is wrong with these rookies?!"
Tanjiro saw Gan attempting to flee into the swamp again.
This time, he would not allow it.
Water Breathing • Third Form: Flowing Dance!
Tanjiro's movements flowed like a rushing current.
In a single fluid motion, he closed the distance.
Gan turned in terror
only to see the blade already descending.
His head separated cleanly from his body.
Meanwhile, Cui fled desperately down the alley while clutching his severed arm.
"I can still escape… I can still "
"Inosuke!" Tanjiro shouted. "He's getting away!"
Inosuke immediately prepared to chase him.
But Zenitsu remained standing motionless with his eyes still closed.
"He won't escape," Zenitsu said quietly.
The air around him crackled.
Zenitsu inhaled deeply.
His legs tensed.
Lightning exploded around his body.
"This is the second time I've used this tonight…"
Thunder Breathing • First Form: Thunderclap and Flash • Godspeed!
A golden streak instantly tore through the alley.
Zenitsu bounced between the walls at blinding speed, accelerating further with every step.
In the blink of an eye, he appeared directly before Cui.
The demon never even saw the slash.
His head slowly slid from his shoulders.
Silence returned to the alley.
Then Zenitsu's body wobbled slightly.
The lightning faded.
A few seconds later, he opened his eyes groggily.
Seeing the destroyed alley, demon corpses, and Tanjiro's group standing nearby
Zenitsu immediately burst into tears.
"WAAAHHHH! You guys finally showed up!" he cried while clinging to Tanjiro. "This place is terrifying! There are demons everywhere!"