The decision was made. To keep their family together and avoid being treated as prisoners, Seo-jun and Seo-ah accepted the roles of Operational Liaisons for the DPO. While the parents were briefed on logistics and the history of the continent, the children—and the "silent" Heixin—were led to the Testing Arena.
The Arena was a vast, circular stadium carved from anti-magic marble. The air was thick with the scent of ozone and training sweat.
"Listen up," a stern instructor shouted, his eyes lingering on Heixin. "In this world, your 'Otherworlder' status gives you a Mana-core that is naturally more refined. We need to see your rank. Pick up a wooden training sword."
The Test of Power
Seo-jin, only 9 years old but filled with the bravery of a boy who grew up on superhero movies, grabbed a sword. He swung it, and to everyone's shock, a small gust of wind followed the blade.
"Wind affinity. Level 1," the instructor noted, impressed. "Not bad for a kid."
Then, it was Heixin's turn.
The Overseer watched from the high balcony, sipping tea. "Let's see what the 'Shy One' can do," he whispered.
Heixin picked up the wooden sword as if it were made of glass. He didn't want to break it. He didn't want to break the world. Every time he moved, he had to manually suppress the ocean of power swirling inside his chest.
As he stepped onto the sand, a group of high-ranking DPO trainees—teenagers who had been in this world for years—began to snicker. "He looks like he's going to cry," one joked.
Heixin ignored them. His mind was drifting again.
The Fragmented Memory
[Flashback: The Final Battle]
The sky was blood-red. Heixin was surrounded by ten thousand "Void Knights," the Demon Lord's personal guard. They weren't human; they were shadows of pure malice.
Heixin hadn't even drawn a sword then. He simply walked through them. Every step he took caused the ground to disintegrate. With a single flick of his wrist, a wave of pure white energy—the Primordial Slash—erased the entire army from existence. There was no blood. Just silence.
"Is this all?" he had asked the Demon Lord. "I just wanted a peaceful life."
The Present Reality
"Hey! Are you deaf?" The instructor's voice snapped him back. "Swing the sword at the mana-crystal!"
Heixin sighed. He gripped the wooden hilt. He tried to think of the weakest thing he knew—a butterfly, a blade of grass. He swung the sword with 0.0001% of his strength.
CRACK.
The wooden sword didn't just hit the crystal; it shattered into fine dust. The mana-crystal, designed to withstand a strike from an A-Rank knight, turned pitch black and then exploded into tiny shards.
The arena went silent. The instructor dropped his clipboard.
"I... I am sorry," Heixin said softly, looking down at his empty hand. "It was... fragile."
The Suspicion Grows
Up in the balcony, the Overseer stood up, his tea forgotten. "That wasn't mana... that was raw physical pressure. Who is this boy?"
Seo-ah, seeing the tension, ran over and grabbed Heixin's arm, acting like a worried mother. "Oh, he's always been so clumsy! He doesn't know his own strength, he's just a big, awkward boy!" She laughed nervously, trying to cover for him.
The Overseer narrowed his eyes. "Clumsy? Or a weapon?"
Before he could investigate further, an alarm blared through the spire. A red light pulsed against the stone walls.
"Emergency!" a scout yelled, running into the arena. "A Rank-S Dungeon Break has occurred in the Southern Sector! The monsters are heading toward the civilian settlement!"
The Overseer looked at the family. "Seo-jun, Seo-ah... if you want to prove your worth to the Organization, your first mission starts now. And bring the 'clumsy' boy. We need to see how he handles a real monster."
Heixin looked at the horizon. He could feel the familiar, foul stench of the Demon Lord's remnants. He didn't want to fight, but he looked at Seo-yun and Seo-jin. They were his family now. And he would kill anything that dared to touch them.