As the demon lunged, claws outstretched and desperate, Leo didn't even flinch. He turned his gaze toward the monster, his eyes flat and entirely unimpressed. With the casual grace of someone pointing out a distant star, he lifted a single finger.
"In-sin-deha," he whispered.
A tiny, brilliant sphere of white light materialized at the tip of his finger. A split second later, it streaked forward like a falling star.
The impact didn't just kill the demon; it obliterated him at a molecular level. His physical form, his dark mana, and his very essence were erased from existence in a flash of blinding purity.
In his final microsecond of consciousness, the demon's mind screamed one last thought: Who are these children... these monsters?
"Hey! Leo! Are you crazy?!" Leon's voice thundered through the vault. He had been standing directly in the line of fire behind the demon and had barely managed to teleport away before the white light passed through his previous position.
"You did that on purpose, didn't you?!"
Leo giggled, his childish face betraying none of the lethality he had just displayed. "Don't worry, brother. I altered the spell's matrix to track only one specific target. You would have survived... probably."
"I highly doubt that," Leon snapped, his expression sour as he brushed dust off his tunic.
"Quit whining like a baby," Leo teased. "It wasn't that serious. Anyway, you were having all this fun without me? What even was that ugly-looking thing?"
"It was supposed to be a high-ranking demon," Leon replied, his voice returning to a tone of clinical disappointment. "But I assume it was weakened from being sealed for so long. There is no way a true A-rank would be that pathetic."
Leo's eyes went wide. "A demon?! Why didn't you say so? I've been dying to test some of my newer spells on an actual demon... Ugh, that's so annoying! Now where am I going to find another one?"
Leon began to pace, his eyes scanning the structural integrity of the room. "I suppose my barrier held up well... which reminds me," his voice suddenly dropped an octave, dripping with a curious, academic anger.
"How did you bypass my barrier, Leo?"
"Oh, that?" Leo laughed, waving a hand dismissively.
"I just replicated the mana frequency of your barrier and collided with it. It was like jumping into a river. I think your seal is a bit flawed, honestly—but don't worry, not many people can mimic magic that fast."
"I bet you enjoyed saying that," Leon muttered, his mind already spinning with ways to reinforce his code. "There is definitely room for improvement."
Leon turned back to the rows of dusty shelves lining the back of the vault. He gestured toward a collection of small, ornate jars, each bound by heavy iron chains and glowing talismans. "Anyway... I believe those jars all contain sealed demons or high-grade spirits. There are over a hundred of them here."
Leon looked at Leo. Leo looked at Leon.
A perfectly synchronized, sinister smile spread across both of their faces. They jumped into the air, their voices echoing off the reinforced walls in a joyful, terrifying shout:
"It's experiment time!"
As months turned into years, the subterranean vault became a laboratory of horrors for the demonic realm. Leo and Leon methodically worked through the collection, realizing that truly powerful A-rank demons were rarely sealable; most in the jars were B-rank or lower. Even the "A-rank" demon they had first encountered had likely been weakened by a flawed seal.
By the end of the year, only three jars remained. The rest of the demons had been "researched" to death, their last moments filled with the realization that the two seven-year-olds poking at their essences were far more monstrous than any creature of the void.
While the princes experimented in the dark, a political storm brewed in the light. A bitter dispute erupted between the House of Queen Suzi and the House of Queen Rika. To settle the score without shedding noble blood, a formal duel was decreed: each house would put forward a single contestant, and the last child standing would secure victory for their mother's lineage.
To ensure "fairness," each house used a dice roll to select their champion. However, fate had little to do with the outcome. Both Leo and Leon subtly manipulated the mana around the dice, ensuring they both emerged as the chosen representatives.
The Kingdom hummed with anticipation. The King invited every high-ranking noble to the royal arena to witness the clash. To ensure the safety of the spectators, S-rank palace mages erected a massive, shimmering barrier between the stands and the combat floor.
On the day of the event,Queen Suzi sat at the King's right hand, flanked by two of her children, her eyes fixed on Leo.
Queen Rika sat at the King's left with four of her children, her pride resting entirely on Leon.
As the two young princes stepped onto the sands of the arena, the crowd saw two brothers representing their mothers' honor. But beneath the surface, Leo and Leon shared a secret, jagged smile. They didn't care about the politics or the houses. Since royal decree forbade princes from fighting one another, this was their first and only legal chance to go all out.
The air in the arena began to vibrate. The "researchers" were finally turning their eyes toward the only worthy subjects left in the world: each other.
The two brothers locked eyes, twin sinister smiles spreading across their faces. The air between them crackled with seven years of pent-up rivalry and secret research. As the High Knight raised his hand and signaled the start of the duel, the atmosphere in the stadium shifted from excitement to pure, primal pressure.
In a heartbeat, the princes vanished. To ninety percent of the spectators, they were nothing but blurs of motion and the thunderous sound of impacts. Only the Royal Knights, their eyes widened in disbelief, could track the movement.
Leo and Leon collided in the center of the arena, matching blow for blow, each strike sending ripples of force through the stone floor.
They leaped back simultaneously, creating distance.
"Fireball!" Leon barked. A relentless barrage of flame roared toward his brother. Leo didn't move; he simply manifested a shimmering barrier. With a casual snap of his fingers, the earth groaned. Massive jagged spikes of rock erupted from the floor, lunging for Leon like the teeth of a giant.
Leon danced through the stone forest with predatory grace, appearing suddenly in front of Leo. He threw a single, mana-infused punch that shattered Leo's shield like glass.
Leo's smile didn't falter. "Got you."
The moment the shield shattered, the shards didn't fall; they exploded outward in a kinetic shockwave that sent Leon hurtling back across the arena.
"Why are you playing around?" Leon asked, his voice dripping with annoyance as he slid to a halt.
"I could ask you the same thing," Leo countered, his eyes gleaming.
The crowd sat in stunned silence. The spells they had just witnessed—casual, effortless, and precise—were already at the level of high-ranking mages. And these were eight-year-olds.
"Fine. Let's get serious," Leon said. The emotion drained from his face, leaving behind the cold, empty stare of a researcher.
"Agreed," Leo replied, his own expression turning into a mask of absolute focus.
The tension in the arena became physical. The wind began to howl, swirling around the two boys in opposing currents. Leo raised his hand toward the darkening sky, while Leon stretched his arms forward.
The S-rank barrier, maintained by the kingdom's finest mages, began to spiderweb with cracks. The mages scrambled, pouring their mana into the shimmering wall to keep it from failing.
"Ancient Curse: Black Hole," Leon whispered.
"Ver-Nis In-Sin-Go-La," Leo chanted.
A swirling void of darkness manifested before Leon, while a brilliant, white singularity pulsed above Leo. The two opposing forces were launched, colliding in the center of the arena. Instead of an explosion, there was a terrifying silence. The two spells simply nullified each other, vanishing into a vacuum of nothingness.
The boys began to levitate, their feet leaving the scorched earth. The sky turned an bruised purple, and the earth beneath them began to disintegrate. Suddenly, the mages' barrier shattered completely, unable to contain the sheer output of power.
Between the two brothers, a black void began to rip open, pulsing with shockwaves of toxic energy. The mages abandoned the arena, rushing to form a desperate shield around the King and the terrified nobles. Above them, the very sky began to crack like a broken mirror.
The hole in the firmament grew rapidly, threatening to swallow the palace itself. Leo and Leon remained locked in their trance, their focus so absolute they didn't even notice the world tearing apart around them.
"YOU LITTLE BRATS! STOP NOW!"
The King's voice, amplified by desperation and raw fear, cut through the mana storm.
The shout snapped the boys back to reality. The void vanished instantly. The sky began to knit itself back together, and the heavy, toxic pressure lifted. Leo and Leon dropped to the ground, landing softly, and immediately knelt before the throne, their heads bowed.
"We are sorry, Father," they said in unison, their voices soft, small, and genuinely frightened by the King's fury.
Silence fell over the arena. The energy was gone, but the terror remained. Every noble and knight in the stands looked down at the two "last princes," realizing that the future of the kingdom didn't just have two heirs—it had two gods.
The King, still shaken by the display of power, officially ruled the duel a draw. To maintain peace between the two mothers, he awarded each house a thousand gold coins, though the true prize was the sudden, fearful respect the entire kingdom now held for the two youngest princes.
However, the news of the "Twin Monsters" traveled far beyond the palace walls. It eventually reached the ears of the Ravens, a dark organization obsessed with resurrecting an ancient Demon Lord. They didn't just need power; they needed a vessel capable of containing it. To them, Leo and Leon weren't princes—they were the perfect hosts.
A week later, the Ravens dispatched Luther, an A-rank mage and a legendary sword prodigy. Guided by a palace mole and a set of stolen blueprints, Luther slipped through the royal defenses like a phantom.
He entered Leon's chambers first. With a flick of his wrist, he dispersed a fine sleeping powder over the boy's bed and hoisted the limp prince onto his shoulder. Casting a high-level Invisibility Shield, Luther began his trek toward the other wing.
On his way to Leo's room, Luther brushed past the second prince, Lloyd. The older prince paused, a chill running down his spine as if he had walked through a ghost, but he was too drowsy to investigate and continued to his own room.
Luther successfully "captured" Leo using the same method. Standing in the center of the room with both boys, he activated a long-range teleportation circle, whisking them away to a hidden stronghold deep within the Ravens' territory.
Luther materialized in a dimly lit throne room and dropped the two boys unceremoniously onto the cold stone floor. He bowed deeply to the man seated on the obsidian throne.
"My Lord, the specimens are here. It was as easy as we planned," Luther boasted, stepping aside.
"So... what's next?"
The voice didn't come from Luther or the man on the throne. It came from the floor. Leon sat up, casually dusting off his sleeves, his eyes sharp and completely awake.
"Are we done playing pretend yet?" Leo asked, standing up beside his brother and stretching his limbs.
Leon turned to Leo, his brow furrowing. "You weren't asleep? You were faking it?"
"Hey, don't blame me!" Leo countered stubbornly. "I saw you get 'kidnapped' and I knew immediately you were faking it just to see where they'd take you. If you're going on a secret field trip, I'm coming too. You're not having fun without me!"
"You just copied my idea," Leon scolded. "You're a fake."
"I don't care! You're not leaving me behind again!" Leo hissed back.
"What is this? Is this some kind of joke?"
The man on the throne stood, his shadow looming large over the boys. This was Arthur Winfield, one of the Seven Heads of the Ravens and the seventh-ranked mage in their league. He walked toward them, his face contorting with a mixture of confusion and burgeoning rage.
The two princes continued to bicker, completely ignoring the high-ranking dark mage and his elite subordinate. To them, Arthur was nothing more than a tour guide for their new playground.
Arthur's fury finally boiled over. The air in the room grew heavy enough to crack the floorboards.
"How dare you ignore me, you insolent brats!" Arthur roared, his aura exploding outward. "I will show you the true power that brings every soul to its knees!"
He stretched his hand toward them, his eyes glowing with malevolent intent as he uttered the familiar command:
"Gravity!"