Tonight is another full moon.
The cold moonlight envelops the earth. Amidst a series of continuous mountains, there is one mountain that stands out. It is as if it is surrounded by the other mountains, enjoying the status of being the center of attention.
On a mountain path, a group of over a dozen young individuals, all wearing Demon Slayer Corps uniforms and wielding Nichirin Swords, carefully make their way into the depths of the forest.
The surroundings are eerily quiet, with no sound of birds or insects. Only the sound of the team's footsteps and their hurried breathing can be heard, creating an unsettling atmosphere that makes everyone's palms sweat.
None of them notice several pea-sized, snow-white spiders emerging from the nearby bushes. Using the cover of night, the spiders climb onto the team members.
Suddenly, the team leader, a young man named Nakamura, lowers his head, slowly turns around, and unsheathes his Nichirin Sword, pointing it at his comrades. The sound of the sword scraping against the sheath is piercing.
The others look at each other in confusion, but given the eerie environment and Nakamura's strange behavior, many grow wary, taking small steps back to create distance and tightening their grip on their swords.
One team member asks, "Nakamura, what's wrong? Did you notice something suspicious?"
Nakamura, trembling with fear, mechanically raises his head and says, "I... I can't control myself."
As soon as he finishes speaking, he swings his Nichirin Sword and charges at two nearby team members.
"Get... get out of the way!"
One team member isn't quick enough and gets slashed across the face, screaming in agony as blood gushes out.
"I... I didn't mean to. I don't know what's happening. I can't control myself. Someone... help me." Nakamura pleads while swinging his sword again.
Faced with a comrade's frenzied attack, the team is momentarily paralyzed, unsure whether to fight back or not. They can only dodge and shout for Nakamura to stop.
Soon, everyone realizes they are experiencing the same terrifying phenomenon—unable to control their bodies and attacking each other. They feel the same fear and despair Nakamura did.
In the forest, screams and cries mingle as the group of over a dozen slashes at each other without dodging, allowing blood to splatter freely.
Even in death, they continue to swing their swords until the last one falls. Only then does the swinging stop.
The forest falls silent again as the white spiders, having gorged on the fresh blood, scurry back into the bushes with their swollen bodies.
At the Ubuyashiki residence.
Kagaya Ubuyashiki sits on the veranda with a smile, accompanied by two of his daughters.
A black dot floats in the night sky, gradually revealing itself to be a Kasugai crow. The crow dives into the yard, struggling to stand before ultimately collapsing.
One of the little girls walks into the yard, gently picks up the dying crow, and brings it to Kagaya, placing it in his hand.
Kagaya tenderly strokes the crow, which weakly opens its beak to speak.
"Is that so? Dozens of children dead... What a pity. They were all good kids. The enemy must be very strong. Could it be the Twelve Kizuki? Nichika, inform Shinobu and Giyu to come here."
"Yes." The little girl respectfully exits the room.
Shortly after, the Insect Hashira, Shinobu Kocho, and the Water Hashira, Giyu Tomioka, kneel in the room.
"Shinobu, Giyu, I'll have to trouble you two to visit Mount Natagumo. Tanjiro, Hatsune, and three others are already on their way there. Let's hope those children are alright."
Hearing Hatsune's name, Shinobu smiles happily. "So, those two completed the task at Shimizu Town? They are quite capable! Oh, how wonderful it would be if humans and demons could coexist peacefully."
These were words often spoken by Shinobu's sister. Imitating her sister's tone, Shinobu feels as if she has truly become her.
Giyu, with a blank expression, glances coldly at Shinobu and says, "As long as demons continue to eat humans, peace between humans and demons will never be possible."
Three young boys of similar age walk along a country road.
The boy in front, with red hair and a red scar on his forehead, wears a green checkered haori over his Demon Slayer uniform and carries a dark wooden box on his back.
Following him is a boy wearing a boar head mask, shirtless with a fur skirt.
At the rear is a blond boy, wearing a yellow checkered haori over his Demon Slayer uniform.
These three, Tanjiro Kamado, Zenitsu Agatsuma, and Inosuke Hashibira, met during a mission. After completing their task, they temporarily rested at a "hidden" base before receiving the mission to go to Mount Natagumo together.
Now, the three have arrived at the foot of Mount Natagumo. Looking at the dark mountain ahead, it seems like a giant spider lurking in the darkness, watching them intently.
Zenitsu, with his naturally timid personality, constantly fears dying without cause. He is highly reluctant about this mission and has been muttering non-stop along the way.
As they draw closer to Mount Natagumo, Zenitsu becomes increasingly anxious, suddenly letting out a scream.
Hearing this, Tanjiro and Inosuke stop and turn to Zenitsu.
"Zenitsu, what's wrong?" Tanjiro asks with concern.
Zenitsu, terrified, points at the mountain and stammers, "D-don't you think this mountain looks scary? It's pitch black and terrifying. I don't want to go. We'll die."
Tanjiro, initially thinking Zenitsu sensed something unusual, is puzzled by such a vague reason. How can he know there is danger without entering the mountain? He exchanges a glance with Inosuke.
Inosuke scoffs disdainfully and taunts, "Hmph, you're so cowardly. How did you even join the Demon Slayer Corps?"
During their conversation, Tanjiro suddenly smells a strong scent of blood ahead.
"I smell blood."
Without further delay, Tanjiro rushes towards the source of the scent, with Inosuke following closely. Zenitsu hesitates but eventually follows as well.
They find a Demon Slayer lying on the ground, severely injured and holding a Nichirin Sword. The "Destroy" kanji on his back is particularly striking.
Hearing footsteps, the injured slayer looks up, hoping for rescue upon seeing the newcomers' uniforms. But when he sees their ranks, hope turns to despair.
"Why aren't you Hashira? Why aren't you Hashira?" He cries in despair, pounding the ground.
"What happened?" Tanjiro approaches, trying to help him up.
But before he can reach, the slayer is suddenly yanked into the dark forest, screaming, "Quick... inform headquarters, send..."
Before he can finish saying "Hashira," a final scream echoes from the forest.