The days that followed settled into a rhythm.
Eren woke before dawn, worked cleaning contracts with Kasim, fed what he could to his dungeon, and visited his family when the credits and vouchers piled high enough. But beneath the surface routine, something else was growing.
The hunter qualification test was in four days.
And Beelzebub—his other self—had never held a sword.
---
It was Kasim who put the thought in his head.
They were riding the mag-rail back from a C-rank dungeon cleanup, the morning sun painting Ironvale's spires in shades of gold and grey. Kasim was scrolling through his tablet, watching highlights from the previous day's hunter matches.
"See this?" Kasim said, turning the screen toward Eren. A young hunter—maybe nineteen, all flash and bravado—was swinging a greatsword twice his size at a training dummy. The strikes were powerful but wild, overcommitting, leaving his entire side open. "Guy's got A-rank strength, but his form is garbage. Watch."
The video cut to a sparring match. The same hunter charged at an older woman with a plain steel longsword. She didn't move. She just shifted her blade three inches to the left, and he impaled himself on it.
"Dead," Kasim said flatly. "Ten seconds in. All that power, nothing to aim it with."
Eren watched the clip again. The young hunter had been stronger. Faster. More mana than his opponent by every measurable standard. But the older woman had skill. She knew where to stand, when to move, how to let momentum do the work.
Raw power without skill is a liability.
The words lodged in Eren's chest and didn't leave.
---
That night, in his cramped apartment, Eren sat on the edge of his bed.
His other self stood guard in the void, greatsword resting point-down on the obsidian floor. The blade was a weapon of immense power—capable of cutting through steel, of drinking light, of ending most fights before they began. But against a skilled opponent? Someone who knew how to read a strike, how to parry, how to use leverage?
The Demon King's raw strength meant nothing if he didn't know how to use it.
I need to learn, he thought. We need to learn.
Eren pulled out his phone and opened the public hunter forums. There were hundreds of tutorial vids—basic forms, footwork drills, sparring breakdowns. Most were aimed at aspirants preparing for the qualification test. Perfect.
He leaned back against the headboard, phone in hand, and pressed play.
In the void, Beelzebub shifted his grip on the greatsword. Ready.
---
The instructor was a retired A-rank hunter, a woman with silver hair and a voice like gravel. She stood in a simple training yard, a wooden sword in her hands, and demonstrated the basic guard positions.
"Your stance is your foundation," she said. "Too wide, and you can't move. Too narrow, and you'll fall when the first strike comes."
Eren watched the screen. Beelzebub moved.
In the void, the Demon King rose to his feet, greatsword in hand. He adjusted his stance. Feet shoulder-width. Knees bent. Weight balanced.
Eren's eyes tracked the instructor's posture. The knowledge flowed across the connection. Beelzebub's feet shifted.
Too far forward. Correction. Better.
The video continued. The instructor moved through the eight basic cuts—vertical, horizontal, diagonal, thrust. Each motion was broken down into its components: where the feet went, how the hips turned, where the eyes looked.
Eren watched. Beelzebub practiced.
The first cut was clumsy. The blade wobbled, the edge coming down at the wrong angle, the follow-through pulling him off balance.
Eren rewound the video. Watched the instructor's foot placement again. Studied the angle of her hips, the line of her shoulders.
The power comes from the legs, he realized. Not the arms. The arms just guide it.
He pressed play.
Beelzebub reset his stance. This time, he focused on the legs. The drive from the ground. The rotation of the hips. The arms stayed loose, guiding the blade rather than forcing it.
The second cut was better. Still rough, but the edge was straighter, the finish more controlled.
Eren watched. Beelzebub practiced.
Again.
The third cut was cleaner.
Again.
---
An hour passed. Then two.
Eren sat on his bed, phone propped against his knee, eyes fixed on the screen. He didn't need to move. He didn't need to practice. His body wasn't the one learning the blade.
Beelzebub moved through the drills. Each repetition was smoother than the last. The greatsword, once a clumsy weight, was beginning to feel natural. The cuts were becoming crisp. The footwork was becoming automatic.
Eren scrolled to the next video: basic footwork drills. Pivot steps. Lunges. Recovery.
Beelzebub's feet scraped against the obsidian, tracing patterns in the dark stone. Pivot. Lunge. Recover. The movements were mechanical at first, then fluid, then instinctive.
Another video: parries. How to deflect a strike rather than block it, using the opponent's momentum against them.
Beelzebub adjusted his grip. The greatsword moved in short, sharp arcs, redirecting imaginary blows.
Another video: counters. How to read an opponent's weight shift, how to bait a strike, how to turn defense into attack.
The demon's blade carved through the void, faster now, more precise.
Eren watched. Beelzebub practiced. The knowledge flowed.
---
Four hours after he started, Eren's phone buzzed.
He glanced at it. Kasim: Early job tomorrow. D-rank dungeon. Be at the east gate by 5.
He typed back: I'll be there.
Then he looked at the video still playing. The instructor was demonstrating advanced combinations now—chains of cuts, feints, recovery techniques.
He let it play. His eyes stayed on the screen. His other self kept moving.
He would watch. He would learn. Beelzebub would practice.
And when the test came, both would be ready.
---
The next morning, Eren met Kasim at the east gate before dawn.
"You look different," Kasim said, studying him. "Sharper. Like you've been working on something."
Eren shrugged, pulling on his gloves. "Got some sleep."
Kasim snorted. "You always say that."
They walked toward the dungeon gate, a D-rank breach in an old warehouse district. The cleanup was routine—a dozen Goblin corpses, a Gnoll warrior, nothing special.
But Eren's mind was elsewhere. In the void, Beelzebub was already moving through the morning drills. Vertical cut. Horizontal. Diagonal. Thrust. The movements were fluid now, almost effortless.
While his human hands stripped corpses and bagged salvage, his other self practiced. Two bodies. Two tasks. One mind, fully present in both.
Kasim noticed something was different. "You're quiet today."
"Thinking," Eren said.
"About what?"
Eren's hands paused on a Goblin corpse. He thought about his other self, greatsword extended in a perfect forward guard. He thought about the cuts he'd practiced a thousand times, the footwork drills, the parries.
"The test," he said.
Kasim nodded slowly. "Good. Someone should make it out of this shitty job."
They worked in silence after that. But Eren could feel Kasim watching him, measuring him, wondering.
He didn't mind. Let him wonder.
---
That night, the training continued.
Eren sat on his bed, phone in hand, scrolling through more advanced tutorials. Parries against overhead strikes. Ripostes. How to fight against faster opponents, stronger opponents, multiple opponents.
In the void, Beelzebub moved through the drills.
The greatsword was heavy, but the weight was becoming familiar. The balance was becoming intuitive. Eren could feel the blade now—not as a separate object, but as an extension of his will, channeled through his other self.
He watched a video on fighting with a heavy blade. The instructor explained momentum management—how to let the weight work for you, how to recover after a heavy swing, how to chain strikes without losing control.
Beelzebub adjusted his grip. He ran through the eight cuts again. This time, he let the weight carry him. The blade swung wider, faster, but the recovery was smoother. The follow-through flowed into the next cut.
Eren watched. Beelzebub practiced. Both learned.
---
Three days before the test, Eren's mother called.
"You're coming for dinner?" Lena asked. Her voice was tired, the way it always was after a double shift at the distribution center.
"I'll be there," Eren said. He was sitting on his bed, phone pressed to his ear. In the void, Beelzebub was running through the footwork drills, greatsword carving arcs through the darkness.
"Good. Mira's been practicing her forms. She wants to show you."
Eren smiled despite himself. "Tell her I'm looking forward to it."
The call ended. Eren sat for a moment, then stood. He walked to the small window and looked out at Ironvale's spires.
In the void, Beelzebub completed a perfect combination—vertical cut, pivot, horizontal cut, lunge, thrust. The movements flowed together like water.
Three days, Eren thought. Then everything changes.
He closed his eyes. In the void, his other self sheathed the greatsword and stood at attention, burning eyes fixed on the darkness below.
Ready.