Just as the atmosphere reached its peak of awkwardness, a sudden commotion erupted from the front of the carriage.
The terrified screams of passengers, punctuated by the dull thuds of impact, drifted back to them in frantic bursts.
The boisterous smile instantly vanished from Kyojuro Rengoku's face. He stood up abruptly, his Nichirin Sword clearing its scabbard with a sharp shing, the blade flashing coldly in the dim light.
He stared at the demon before him—a towering creature with sickly, blue-grey skin. "You used a Blood Demon Art to hide that massive frame of yours, didn't you? No wonder you were so difficult to detect. But since you have dared to slaughter innocent people, I shall cut you down!"
Before he had even finished speaking, the blue-faced demon lunged at Rengoku, its maw agape, a foul, metallic stench wafting ahead of it.
Rengoku's eyes sharpened. Instead of retreating, he stepped forward to meet the charge. "Flame Breathing, First Form: Unknowing Fire!"
A blur of crimson flames swirled with the wind of his blade, instantly engulfing half of the demon's body. With a single, harrowing shriek, the creature dissolved into a pile of black ash.
"So incredible!" Aoi watched him, her eyes wide with genuine admiration.
Rengoku didn't linger. He turned and sprinted toward the next car. "There's another one! Follow me!"
Aoi called out in response and followed immediately, with Tanjiro and the others hot on their heels.
They burst into the next carriage to find a demon with grotesque, elongated limbs—resembling a spider—clutching a passenger by the throat.
"Let him go!" Rengoku roared. He launched himself forward like an arrow from a bow, his Nichirin Sword wreathed in roaring flames as he slashed at the demon's arm.
Aoi took the opening to rush in, pulling the paralyzed passenger to safety. She turned and shouted to the trio, "Tanjiro! Evacuate the other passengers! Don't let them get caught in the crossfire!"
The three boys moved instantly. Once Rengoku saw the passengers were clear, he focused entirely on the target.
"Flame Breathing, Second Form: Rising Scorching Sun!"
Red-hot flames spiraled upward along the blade, forming a pillar of fire that engulfed the spider-demon until nothing remained but ash.
"You're amazing! Big Brother, that swordsmanship was masterful! Please, take me as your Tsuguko!" Tanjiro's eyes were practically glowing. He stepped forward excitedly, hands pressed together in a fervent plea.
"Me too!"
"I want in, too!"
Zenitsu and Inosuke shouted in unison. Surrounded by the enthusiastic trio, Rengoku let out a hearty laugh. "No problem at all! I'll take all three of you under my wing as a set!"
Watching the scene, Aoi couldn't help but let her lips curl into a smile.
Suddenly, her vision went black. It felt as though she had been plunged into deep water; a cold, sluggish numbness seeped into her limbs and bones.
After an indeterminate amount of time, a gentle female voice called her back to consciousness. "Aoi? Aoi, honey, wake up. It's time to get out of bed."
Aoi snapped her eyes open, squinting against the harsh, bright sunlight. She sat up, glancing around in a daze. This is... my room...?
A woman walked in then, her eyes curved in a smile, her expression radiating a warmth identical to the mother in her memories.
"Mom...?" Aoi's voice trembled, her eyes instantly welling with tears.
The woman reached out to brush the cold sweat from Aoi's brow, her voice laced with motherly concern. "Why are you crying? Did you have a scary dream?"
Aoi's throat tightened, a sharp ache rising in her nose. She reached out to grab a corner of the woman's sleeve, but just as her fingertips were about to make contact, she froze.
Wait... no.
No, her mother had died in that fire...
[Ding—System Ultimate Warning: Dream Core Illusion detected! Anchor Lock failed! Host's mental energy depletion rate is accelerating!]
The sharp, mechanical warning pierced her brain like a needle. Aoi shuddered and violently yanked her hand back. She looked at the smiling "mother" before her, her heart feeling as though it were being squeezed by a giant hand.
"You aren't my mother," Aoi said, her voice shaking but her resolve absolute.
"Silly child, how could I not be your mother?" the woman said, reaching out to take Aoi's hand.
Aoi stared at the woman, fighting back the stinging in her eyes. She shouted every word with conviction: "I don't belong here! I'm on the Mugen Train! I have to go back!"
The moment the words fell, the entire room shattered like a broken mirror, collapsing into nothingness.
Meanwhile, inside the train carriage, Tanjiro and the others were slumped in their seats, deep in sleep. Their brows were knit tight, and they muttered fragments of sentences, clearly struggling to break free from their own dreams.
Suddenly, the box behind Tanjiro clicked open. Nezuko, her dark hair a bit of a mess, poked her small head out. Her ruby-red eyes scanned the carriage warily.
She caught the thick, cloying scent of a demon. Her small brow furrowed as she gripped the edge of the box and hopped lightly onto the floor.
Seeing Tanjiro unconscious and unresponsive, Nezuko let out an anxious, low whimper. She trotted over and tried to shake him awake.
But Tanjiro didn't react. His brow only furrowed deeper as he mumbled, "Takeo... Rokuta..."
Seeing that shaking him did nothing, Nezuko took a half-step back and suddenly slammed her forehead into Tanjiro's.
BANG!
Tanjiro's forehead didn't have a scratch on it. Instead, it was Nezuko's forehead that split open, blood trickling down.
The droplets slid down from the corner of her brow, landing on Tanjiro's cheek. Nezuko let out a pained "Muuu!" and tears immediately began to swirl in her eyes.
Getting a little angry now, she activated her Blood Demon Art and headbutted him once more.
Tanjiro's eyelashes fluttered violently, and his pinched expression began to soften.
In his dream, Tanjiro raised his Nichirin Sword and drew it across his own throat. Blood splattered against the frozen snow. By "dying" in the dream, he snapped his eyes open in reality, only to be met by Nezuko's tearful face.
"Nezuko! Are you okay?"
Seeing Tanjiro lean in, Nezuko instinctively covered her own forehead, terrified he was about to deliver a return headbutt.
Relieved that Nezuko was unharmed, Tanjiro let out a breath. He looked around to find everyone else still trapped in the slumber, their hands tied to several strangers by lengths of rope.
Tanjiro looked down at the severed rope on his own wrist and thought for a moment. He turned to Nezuko and said, "Nezuko, please use your Blood Demon Art to burn the ropes on everyone's hands."
Nezuko nodded her small head, a look of serious determination flashing in her ruby eyes. She stood on her tiptoes, raising her small hands as a faint, crimson glow emanated from her palms.
Aoi felt a massive pulling force, as if she were being yanked violently from the bottom of the ocean. The air was suddenly sucked from her lungs, causing her to cough violently.
The dark mist before her eyes vanished. The warm, tatami-matted room was gone, replaced by the dim, swaying car of the train.
"Tanjiro..."