Part I: Late Arrival and a Lingering Question
The sun had already begun its descent when Kaito returned to the Thunder Estate, his footsteps slower than usual. His blade was clean, his supplies intact, but his mind was heavy.
The old man was waiting on the veranda, sipping tea with one eye open and the other squinting toward the path.
"You're late," he said, voice light but edged.
Kaito bowed. "I ran into trouble."
The master raised an eyebrow. "Trouble with rice vendors?"
"Demons," Kaito said. "Four of them. Weak, but reckless. I dispatched them quickly."
The old man's expression shifted—less surprise, more concern.
"Four? In a single village alley?"
Kaito nodded. "They weren't coordinated. Just hungry. Desperate."
The master set his cup down. "That's not normal. Even for low-tier demons."
Kaito sat beside him, the weight of the encounter still pressing against his ribs.
"I've been wondering," he said. "How many demons are there? Not just the Twelve Moons—but all of them."
The master exhaled slowly.
"No one knows the exact number," he said. "Muzan creates them. Some are born from his blood directly. Others are turned by his agents. Most are unstable—burn out within weeks. But the ones who survive… they spread."
Kaito frowned. "So there could be hundreds?"
"Thousands," the master corrected. "Scattered across Japan. Some hide in forests. Others blend into cities. A few even live among humans, feeding slowly to avoid detection."
Kaito's grip tightened. "And we're supposed to stop them all?"
The old man chuckled. "No. We're supposed to stop the ones we find. The ones who threaten. The ones who kill."
He leaned forward.
"That's why your training matters. That's why your instincts matter. Because you won't always have backup. You won't always have time."
Kaito nodded, absorbing the scale of the war he'd stepped into.
"Four demons in one alley," he repeated. "And I was lucky they were weak."
The master stood, brushing dust from his haori.
"Next time, they won't be."
He turned toward the training hall.
Part II: Gravemark's Gifts and Thunderous Pranks
Inside the Thunder Estate's training hall, the air was still. Kaito knelt in the center, eyes closed, as Gravemark pulsed quietly within him.
Three glowing nodes shimmered in his mind—each one a skill born from the first branch. He didn't speak. He didn't explain. The system was his secret. His edge.
His master sat nearby, sipping tea and watching with one eye open.
"You've been moving differently," the old man said. "Your stance is heavier. Your pivots are tighter."
Kaito nodded. "I've been… refining my control."
The master grinned. "You sound like a swordsman, not a boy."
Kaito didn't mention Gravemark. He didn't describe the interface or the points. He simply said, "I've been listening to the terrain."
The system pulsed again.
Gravemark Branch I: Skill Options
Anchor Step
Description: Locks Kaito's stance mid-combat, allowing him to absorb impact and redirect force.
Tactical Use: Ideal for countering heavy attacks or holding ground against charging enemies.
Drawback: Limits mobility during activation—requires precise timing.
Weighted Arc
Description: Adds gravitational torque to sword swings, increasing impact force and destabilizing enemy footing.
Tactical Use: Excellent for breaking guards or disrupting demon balance. Drawback: Slightly slower swing speed—requires rhythm control.
Graviton Pulse
Description: Emits a short-range shockwave from the feet, knocking back enemies and interrupting movement.
Tactical Use: Useful for crowd control or escaping tight formations. Drawback: High stamina cost—can only be used twice per engagement.
Kaito studied each one.
He didn't choose yet.
His master leaned in. "You look like you're picking a dessert menu."
Kaito smirked. "They're all good."
The old man stood and stretched. "Well, while you're busy becoming a mountain, I've got something for you."
He walked to the corner and returned with a folded cloth.
"Your new training haori," he said, handing it over.
Kaito unfolded it.
It was bright pink.
With glittering lightning bolts stitched across the back.
He stared.
The master burst out laughing. "You should've seen your face!"
Kaito blinked. "You made me fight four demons and then gave me this?"
"Tradition," the old man said, wiping tears. "Every Thunder student gets pranked once."
Kaito nodded slowly.
"Understood."
That night, while the master slept, Kaito crept into the forge room. He adjusted the weight settings on the master's training sandals—doubling them.
The next morning, the old man stepped outside, took one stride, and nearly face-planted.
"What in the—my legs feel like bricks!"
Kaito appeared behind him, sipping tea.
"Tradition," he said.
The master stared.
Then laughed.
"Alright, alright. You're officially one of us."
They sat together, watching the clouds roll past.
Gravemark pulsed quietly.
Three skills waited.
And Kaito was ready to choose.
But he would choose alone.
The system was his burden.
And his blade would carry it in silence.
Part III: Selection, Farewell, and Return
Kaito stood in the training hall, the three Gravemark skills pulsing in his mind like silent drums. After careful thought and sparring simulations with his master, he made his choice.
Selected Skill: Anchor Step
The moment he confirmed it, the system responded. His stance deepened. His center of gravity adjusted. Anchor Step wasn't flashy—it was foundational. It gave him control, stability, and the ability to absorb force like a rooted tree in a storm.
For the next few days, Kaito trained relentlessly. His master guided him through terrain drills, impact tests, and counter-strike timing. They laughed, argued, and shared meals under the thunderclouds. The pink haori prank faded into memory, replaced by respect.
On the fifth morning, Kaito felt the shift.
Stormseed pulsed.
Gravemark shimmered.
The worlds were aligning again.
He bowed deeply to his master. "Thank you—for everything."
The old man smiled. "Go shake the other world. And don't forget—lightning needs grounding."
Kaito stepped into the mist.
The Thunder Estate faded.
And the skyline of Saitama returned.
He was ten again.
But now, he carried gravity in his bones.
And the storm had learned to stand.