After bidding farewell to Tanjiro, Lucas turned to look at Zenitsu, who was still staring off into space in a daze.
Without saying a word, Lucas stepped forward, grabbed Zenitsu by the back of his collar, and began marching up Fujikasane Mountain.
As they drew closer to the demon-infested mountain, the air grew heavier. Zenitsu finally snapped out of his stupor, his arms flailing in panic.
"Lucas, what are you doing?! Don't rush ahead like that!"
He grabbed at Lucas's arm, voice rising in fear. "Please! There are really demons up there! What if we get eaten alive?!"
The further they walked, the softer Zenitsu's voice became, like he was scared the very sound of his voice would summon monsters from the shadows.
Lucas ignored his pleas, continuing forward as his eyes swept across the surroundings. The mountain was blanketed in towering trees, their thick branches crisscrossing above to blot out the sun. The deeper they ventured, the darker and more foreboding it became.
After walking for a while, Lucas's steps suddenly halted.
Zenitsu's sniffling and muttering stopped as well. His body stiffened as if he had been frozen solid.
"I—I hear something," Zenitsu whispered. He pointed a trembling finger toward a dense patch of forest ahead and to the right. "There's a terrible sound over there…"
Lucas turned in that direction. Thanks to Zenitsu's shared talent, he could hear it too—a low, grating noise that clawed at the edges of his hearing.
Then, from within the shadows of the trees, a creature emerged.
It was gaunt and grotesque, with skin like dried bark and glowing red eyes. Bone spurs jutted from its arms like daggers.
> [Bone Demon]
Race: Demon
Rank: Mizunoto
Aptitude: Inferior
Quality: Low
Talent: None
Skills: Pounce (Mastered), Bite (Mastered)
The creature's lips curled into a wicked grin as it took in the two boys.
"Well, well... What luck. Two little morsels at once. Looks like I'm eating well tonight."
It dragged its tongue across its lips, a foul gleam in its eyes.
Lucas read over the demon's information, and immediately, all interest vanished. Making friends with demons was a possibility—but not this one. None of its attributes matched what he needed.
The Bone Demon frowned slightly, noticing the lack of fear on Lucas's face.
What was this expression? Was it… disgust?
Shouldn't the boy be trembling in terror, eyes wide with panic? Instead, he looked almost bored.
Annoyed, the demon clenched its fists. The bone spurs on its arms extended, gleaming with menace.
"Run, Lucas! It's about to pounce!" Zenitsu cried, panic flaring in his voice.
He tried to grab Lucas's arm and pull him to safety—but Lucas didn't budge. His body was as still and solid as a stone statue.
Zenitsu blinked in confusion. What… was Lucas always this strong?
Still, he stepped forward, placing himself between Lucas and the demon. With trembling hands, he unsheathed his katana, the blade shaking as he held it up.
No. He couldn't run. If he ran now, Lucas would be left behind—and he'd be as good as dead.
Seeing Zenitsu shielding him, Lucas's lips curved into a faint smile.
He didn't faint and unleash his subconscious power. Instead, he stood and protected him—despite being terrified. That was courage.
It made Lucas feel… warm.
The Bone Demon, however, was thoroughly unimpressed.
Was this trembling fool the best the Demon Slayer Corps had to offer? How pitiful.
The demon sneered and began licking the bone spurs on its arms. Then, with a sudden motion, it lunged forward.
Zenitsu's breathing quickened.
His eyes tracked the demon's movements. The sword in his hand wavered, the tip trembling with his nerves.
"Don't be scared… Grandfather said…"
But before Zenitsu could finish the thought, the Bone Demon was already upon him.
Its grotesque body, exposed from the waist up, reeked of blood and rot. Its tongue lolled out, inches away from Zenitsu's face.
Zenitsu froze, his mind going blank from terror.
And then—
Clang!
A flash of golden lightning exploded in the forest.
It illuminated the trees for only a moment, then vanished into silence.
The next thing Zenitsu saw was the Bone Demon—split cleanly in two from neck to hip.
Its lifeless body collapsed to the ground, the head rolling to a stop right at Zenitsu's feet.
Zenitsu stood frozen, staring at the dismembered demon.
Was… was it dead?
That sound just now—was it the sound of a sword being drawn?
Did it come from behind him?
Slowly, mechanically, Zenitsu turned around.
Lucas stood there, calmly sliding his sword back into its sheath.
Zenitsu's throat was dry. He could barely form words.
"Lucas… that was you?"
It couldn't be. Lucas had never passed basic training. He couldn't even keep up with the simplest drills!
But that sword strike—he knew it. He knew it better than anything else.
It was Thunder Breathing: First Form—Thunderclap and Flash.
The way the lightning tore through the air, the sheer speed—it was identical to his Grandfather's technique.
When… When did Lucas become so strong?
"I had an epiphany," Lucas said casually, "after I left Peach Mountain. I learned Thunder Breathing during those two days."
"Two days!?" Zenitsu gaped. "You learned Thunder Breathing in just two days?!"
He could hardly believe it.
He had trained for over a year—day in, day out—and still struggled to master the forms.
Yet Lucas… had done it in two days?
Was an epiphany really that powerful?
Overcome with emotion, Zenitsu suddenly lunged forward and wrapped Lucas in a tight hug.
"You jerk! You could've told me you were so amazing! I was scared to death! I thought we were going to die!"
Lucas was stunned by the sudden hug, but then chuckled softly.
He had thought revealing his strength would make Zenitsu feel left behind or inferior. But instead, his friend was overjoyed—genuinely happy for him.
That was Zenitsu.
As they continued their journey into the forest, several more demons emerged from the darkness.
But one by one, Lucas took them down with a single strike.
To Zenitsu, it looked like Lucas was just slicing through air. The sword light was so fast, so sharp, that he couldn't even track it with his eyes.
Each demon fell without even knowing what hit them.
It left Zenitsu in awe.
This wasn't the same Lucas who could barely do push-ups.
This was someone even stronger than Kaigaku—someone who made Thunder Breathing look effortless.
"Zenitsu, I'm going to take a short rest. Keep watch, alright?" Lucas said, finally settling down at the base of a tree.
"Me? Uh… O-Okay…" Zenitsu stammered, trying to hide his anxiety.
Me? On watch?
What if another demon came?
But he couldn't keep relying on Lucas for everything. He had to be useful too—somehow.
As Lucas sat cross-legged on the forest floor, his eyes closed in a meditative pose, Zenitsu sat nearby with his sword clutched tightly in both hands, eyes darting nervously around.
Of course, Lucas didn't actually need to rest.
The demons they encountered were too weak to tire him out. In truth, he was just taking this moment to fuse Tanjiro's talent.
He had obtained it earlier but hadn't had a chance to fully integrate it into himself.
Now was the time.
A faint interface appeared before his eyes:
> [Do you wish to fuse the talent: Slit Line?]
[Yes]
Lucas didn't hesitate.
He mentally confirmed the prompt.
From now on, with Tanjiro's talent of perceiving enemy weaknesses—the Slit Line—his swordsmanship would reach an entirely new level.
No demon would be able to escape his blade.
And the next target was clear.
Using Tanjiro's fused talent, he would soon track down and defeat the Hand Demon.
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