Deep beneath the fortress city of Ise, in a cavern carved from cold, lightless stone, a man breathed in a slow, rhythmic cycle.
His blood red eyes shifted to the surrounding hundreds of training dummies—some made of wood, others of reinforced iron. He moved through the silence with a grace that was unsettling, his strikes landing with a "thud" that sounded far too heavy for a man of his build.
While his kinsmen grafted limbs, embedded symbiotes, and fermented toxins in their blood, the man had remained "clean."
The main family treated the Shadow Dragon Energy as a supplementary art, something that enhances their hideous martial arts. His was built on the Shadow Dragon Energy itself as his core—until it became a dense, invisible armor around his muscles.
He struck a dummy, and the iron caved in as if it were made of wet sand.
With a handsome face, mid-length black hair, and red eyes, his name was Yujin. The Oni clan patriarch's only son, also called the 'Heretical Prince'.
'Heretical' all because he refused to use the ugly, forbidden, inhumane martial techniques of the Oni Clan. As well as the experimentations that come with it.
His martial path was 'Unbroken Form', centered on the idea of "power without corruption". His philosophy is to never change himself to gain power, but to make power adapt to him.
In a sense, he always wanted to be pure and "clean".
As he moved, a flash of red crossed his vision—not the red of his own eyes, but the blood on the walls from three nights ago.
The face of the Shinken martial artists he had killed to protect his cover, haunted the periphery of his mind.
Unfortunately, they had chosen his exit... of all places.
A necessary sacrifice, he told himself, his jaw tightening. To pull this clan out of the filth of human experimentation, he must first become the monster that rules it.
If he let them go scot-free, with many eyes, he might go under immense scrutiny.
They might even find out about his deal with the Beggar Sect.
"Young Master Kai."
Yujin didn't turn. He already knew the gait of the man standing in the shadows. "What is it, Master Hiraku?"
"You are needed in the courtyard," Hiraku said, bowing low. "The Demon has returned. He seeks a challenge."
Yujin steeled himself, a flicker of genuine surprise crossing his face. "The Demon? You mean Bankei?"
Bankei was the only man in the clan he respected. He broke free from the rot and evil of this place and became a Saint. His father let him go? Why come back?
Hiraku simply smiled. Yujin donned his mask—a sleek, minimalist design that contrasted with the grotesque visages of his peers—and followed the master toward the light.
———
When Yujin stepped out onto the pavilion balcony, the sun felt blinding. He looked down and froze.
Standing amidst the groaning, broken bodies of ten Martial Squires was a figure with his arms folded, draped in a weighted white cape, wearing the unmistakable mask of the Demon.
Yujin activated his Shadow Dragon Sense. The world shifted into hues of black and violet energy.
He analyzed the intruder's Shadow Dragon energy. It was powerful—dense and churning. He also had an aura of a Marital Squire? He saw Mangūsu in the air, unmasked and radiating a jubilant, almost terrifying smile.
Yujin leapt from the balcony, landing softly in the center of the courtyard. The surviving squires scrambled back.
"You aren't Bankei," Yujin said. He dropped into a low, rooted stance. He was on full alert, not sure who this new "Demon" was.
The surrounding martial squires gulped in excitement.
The Heretical Prince is currently the strongest martial squire in the clan. Fighting wars by his side, they were closest to him and knew his strength the best. They were convinced he would not lose.
The battle began without a signal.
Yujin moved with a speed that made the previous squires look like they were standing still. He was a master of Unbroken Grappling Style, closing the distance to wrap his arms around Merun's waist for a high-amplitude suplex.
He lifted. Or rather, he tried to lift.
Merun didn't budge. It was like trying to uproot a mountain with his bare hands. Yujin immediately transitioned, sliding around Merun's back to sink in a standing rear-naked choke. He applied his compressed Shadow Dragon Energy, intending to collapse the windpipe.
Merun didn't even lift his hands to break the hold. He stood there, wordlessly, as Yujin's forearms strained against a neck that felt like solid diamond.
What is this density?! Yujin thought.
He abandoned the choke, dropping low to snatch a single-leg takedown. He drove his shoulder into Merun's thigh and pulled.
Nothing. Merun's center of gravity didn't shift a fraction of an inch.
Yujin tried a flying armbar, swinging his weight to snap the elbow, but his legs simply bounced off Merun's ribs as if hitting an iron hull.
Yujin spiraled away, dodging a counter-strike. For the next several minutes, the Prince was a whirlwind of technical perfection. He tried a guillotine, an arm-triangle, and a spinning heel hook. Each time, the technique was executed flawlessly, but the result was the same: the Demon was un-grappable. His body mass seemed to defy the laws of physics.
Slowly, the damage began to pile up on Yujin. Every time Yujin's strikes or grapples connected, his own bones vibrated with the stress of the impact. His knuckles were bleeding. The skin of his fingers had been torn off. His breathing was becoming ragged. Yet, the Prince refused to stay down.
The Demon seemed to have had seen enough. The Demon's aura flared into a dark, red-black hue that looked like a hyper-concentrated version of the Shadow Dragon Energy.
Merun cupped his hands at his side. The air in the courtyard began to hum.
"KAME..."
His voice reverberated through their chests. The sky darkened, and the air grew heavy with peril.
"HAME..."
Within his cupped hands, an immense amount of energy was condensed.
Its shimmer shone from within Yujin's blood-red pupils. He knelt mesmerized by the technique's beauty.
"HAAAAA!"
The blast roared forward—a beam of blue light threatened to vaporize the courtyard.
The whole world went silent, as if to wait for its moment of destruction.
But before it could hit the Prince, Mangūsu's fully mutated ki-covered beastly hand slammed upward in front of Yujin, swatting the energy beam into the sky where it exploded like a dying star.
As the beam ended, Merun stood still, his chest heaving as if snapping out of a frenzy.
"Enough!" Mangūsu roared, his face split by a manic, wide-eyed grin.
He looked at Merun with pure, unadulterated lust for power. That was the Shadow Dragon Energy technique that Bankei used with such explosive, clean efficiency!
"You have proven yourself," Mangūsu said, actually bowing his head slightly toward the masked Merun.
He felt as if he were looking at a future equal—the perfect culmination of the Sage's vision. "Is there anything else you require?"
Merun looked at Mangūsu, his voice muffled by the mask. "Remember me? I am the Rat, Master Mangūsu."
Mangūsu's eyes widened. He remembered that little shit that was with Bankei. The confirmation sent a jolt of shock through him, followed quickly by a sense of profound kinship. They were on the same side. This monster was sent by the Sage to extract knowledge and eventually replace Bankei!
"I see," Mangūsu whispered, his voice thick with respect. "The Sage's will is absolute."
"Then hear his will," Merun said coldly. "The Sage requires the remains of the Shinken prisoners. He did not say what for."
Mangūsu didn't even hesitate. To a man obsessed with the "New Demon," the request is just another step in the Sage's grand design. "A reasonable request. Hiraku! Fetch a corpse specialist to identify the remains and prepare them for transport. They are his."
"Yes, Master," Hiraku whispered, moving quickly.
Merun turned his head toward Yujin. The Prince was on one knee, coughing up blood, staring at Merun with those blood-red eyes. He was trying to reconcile the "demon" before him with the crushing weight he had just felt.
Not to mention, the humiliating defeat he just went through.
His father had sent him to teach him a lesson, it seems.
But... why take the corpses of the ones he killed?
Merun leaned in slightly, and beneath the shadow of the demon mask, he gave Yujin a deliberate, mocking wink.
Yujin froze. The critically injured man watched in total confusion as the "Demon" leaped on top of the gate's walls, stood straight and folded his arms as his cape fluttered in the wind.
While he was confused, he had to admit; the New Demon looked menacing.