A deafening roar shook the laboratory walls as Arnaud let out a thunderous growl. He stood at his full height, surrounded by a vortex of blood that seemed to flow and contort constantly.

Intricate patterns resembling a jaguar's spots came alive on his surface in a frantic scarlet pulse. His body, though still incomplete, moved with lethal grace driven by pure fury. His jaws opened in a demonic snarl, revealing razor-sharp fangs. His intense red eyes reflected a millennia-old thirst for vengeance. There was no longer room for doubt or remorse. Arnaud had fully embraced his violent and merciless nature.

From the hallway, the cartel's guards watched in growing panic as Dr. Gálvez's supposed "research" came to life before their disbelieving eyes. Some, gripped by horror, tried to flee but Arnaud was too fast.

Screams of agony echoed down the corridor as his claws tore through their flesh. In his wake, Arnaud was reconstituting more and more, adopting a vaguely humanoid form.

Gálvez witnessed the scene with a mixture of terror and scientific fascination, unable to tear his eyes away from the dantesque spectacle. The doctor even seemed to forget the danger for a moment, watching in near-ecstasy as the creature employed its abilities to reconstruct itself at great speed, mutating into something beyond human comprehension.

The first mercenary who tried to stop him was shredded within seconds. Arnaud's claws, now long and sharp, tore through the bulletproof vest like paper, easily rending flesh and bone. Blood gushed in a torrent as the man fell, his choked scream drowned by the monster's roar.

The other mercenaries watched in horror as their comrade was destroyed so quickly. Their attempts to shoot with greater precision and coordination only served to hasten their own demise.

♢♢♢♢

Taking advantage of the commotion, Lola dragged herself away, trying to reach the back of the warehouse where Arturo and Juana were being held, until Miguel spotted her.

In the hostage room, the thugs waiting for orders flinched at the thunderous noise. Riquelme frowned in disgust.

"What the hell is going on here now?" he muttered under his breath.

♢♢♢♢

A mercenary let out a strangled cry as Arnaud appeared before him in the blink of an eye. Before he could react, a scarlet claw grabbed him by the face. The unfortunate man convulsed and shrieked as blood began to fuse with his skin, forcing its way through every opening of his body.

Arnaud let out an ecstatic roar as the surge of fresh blood began to flow into him. He could feel renewed strength coursing through every fiber of his being, cells devouring the vital fluid with ravenous hunger. His body swelled and his muscles tensed even further.

The gunfire continued unabated, but Arnaud barely noticed. Bullets embedded in his skin surface only to be expelled almost instantly. Wounds began to close immediately, flesh reconstituted by the rivers of blood pooling around him.

A pair of mercenaries emptied entire bursts at point-blank range against his head, but only succeeded in ruffling his hair slightly as the thick blood swirled to seal the impacts.

Arnaud swept with his claws, shredding those poor souls in an explosion of flesh and viscera. His jaws opened to devour the juicy remains, crimson fluid gushing from his mouth in a feast of blood and death.

More mercenaries arrived, opening fire with heavier weapons. Bullets exploded against his body, shredding skin and muscle only for the shreds to regenerate instantly thanks to the incessant flow of blood nourishing him. Arnaud roared in maddened ecstasy, the pleasure of the carnage clouding his senses as he hacked and tore his way through.

This content has been misappropriated from Royal Road; report any instances of this story if found elsewhere.

The regenerative ability not only demoralized the mercenaries but filled them with primordial terror. It was as if they were fighting against an unstoppable force of nature, something immortal and relentless.

The mercenaries, aware of their desperate situation, tried different tactics. Some aimed for his head, others attempted to immobilize him with nets and cables, but it was all futile. Arnaud broke any restraint, rose from every fall, and healed from every wound. This deadly game of cat-and-mouse only served to feed his bloodlust and hatred for those who dared defy him.

In a last desperate attempt, the mercenaries resorted to their heaviest weapons. Grenades and explosives were deployed in a frantic effort to stop the monster hunting them.

♢♢♢♢

Gálvez watched with a mixture of terror and scientific fascination as Arnaud shredded the mercenaries one by one. His eyes gleamed with a sickly glow as he scribbled frantic notes on the dantesque spectacle unfolding before him.

"Incredible! Simply incredible!" he muttered through gritted teeth. "An unprecedented cellular regeneration and self-healing ability..."

Suddenly, Arnaud turned towards him, his pitiless red eyes boring into the terrified scientist for a moment. Gálvez flinched and stumbled back.

"Riquelme! Riquelme, get me out of here now!" he choked out. "The experiment has gone out of control!"

Riquelme's heavy footsteps echoed down the hallway as the cartel leader responded to the call. His face twisted into a furious scowl at the sight of the shredded bodies of his men.

"Tell me what the hell is going on, Gálvez," Riquelme demanded in a menacing tone. "Didn't you have your experiments under control?"

The scientist shook his head frantically, his face beaded with cold sweat.

"I don't understand, boss. Those cell samples seemed inert, a mere biological remnant of a supernatural specimen..." He swallowed hard before continuing. "The regeneration was slow... But something must have activated them, triggering this large-scale regenerative and mutative ability..."

"And how do we stop that thing?" Riquelme interrupted impatiently.

Gálvez averted his gaze, wringing his hands nervously.

"I-I'm still working on that..."

"You'd better find a solution fast, Gálvez," Riquelme growled through gritted teeth. "Or you'll be the next one on the dissection table..."

♢♢♢♢

Meanwhile, Miguel had managed to drag Lola to one of the back storerooms of the warehouse, near where Juana and Arturo were being held. The poor woman could barely move due to her wounded leg.

"We'll be safe here, for now," Miguel muttered in a trembling voice, rubbing his cheek.

Lola looked at him with a mixture of fury and disappointment.

"How could you get involved with these people, Miguel?" she spat between gasps. "Can't you see the monster Riquelme is?"

The man averted his gaze in shame.

"I know, I know… I was an idiot," he admitted in a thin voice. "But you have to understand, Lola. I needed the money, my daughter was very sick..."

He covered his face with his hands.

"And you think that's fair in exchange for so many innocent lives?" Lola berated him harshly.

♢♢♢♢

Arnaud was in a frenzy, driven solely by rage and the instinct to kill. His eyes had lost all trace of humanity or consciousness, turned into blazing red orbs fixed on the massacre. Limbs, weapons and severed body parts flew in all directions as he tore through like a hurricane of claws and fangs.

Suddenly, a thunderous explosion rocked the place when a grenade impacted at his feet. The sudden blast of heat and shrapnel threw him against a wall, opening a huge breach. For an instant, his battered and lifeless body lay exposed… until the first tongues of blood began to fuse with the shredded flesh.

For a brief moment, it seemed Arnaud had been brought down.

The mercenary leader, his face covered in sweat and desperation, shouted orders for his men to continue the attack. But their efforts were in vain. From the smoke and rubble emerged Arnaud, more furious and monstrous than ever. His body, now covered in blood and ash, regenerated before their eyes, defying all logic and rationality. The mercenaries' hope dwindled with every step Arnaud took towards them.