The impact of my first step against the arena's polished floor echoed like the firing of a heavy artillery cannon, cracking the stone slabs beneath the soles of my boots and propelling my body forward at a speed that surpassed the sound barrier. The mass of purified mana I had accumulated in my core instantly expanded throughout my entire muscular system, enveloping my body in a golden aura of astonishing density. On my left side, Scarlet advanced like a crimson blade cutting through the darkness of the underground chamber, keeping her body lowered and her long sword aligned at a perfect penetration angle. On the right side, Rai'kanna used the momentum of her own weight to hurl her heavy alloy spear along a devastating parabolic trajectory, whose trail of cutting wind carved a deep furrow into the basalt floor.
The Chimera Dragon noticed our assault at the exact millisecond we crossed the arena's containment perimeter. The central dragon head rose with a visceral roar that made the hall's ceiling tremble, dislodging fragments of rock and massive stalactites that came crashing down onto the battlefield. Simultaneously, the abyssal feline head on the left side roared at a shrill frequency, thrusting its front paw, covered in obsidian claws, toward Scarlet's trajectory, while the serpent head on the right opened its jaws filled with venomous teeth, firing a blast of acidic toxins toward Rai'kanna's attack path.
"Deflect the blast on the right!" Rai'kanna shouted, interrupting her advance for a fraction of a second to deliver a circular strike with the rear end of her spear, generating a whirlwind of pure wind that deflected the stream of green poison away from her body, sending it crashing against the side wall with a terrifying corrosive hiss.
"She's mine!" Scarlet shouted coldly, leaping with surgical precision over the abyssal feline's claws and delivering an oblique slash that cut through the monster's skin from its shoulder to its chest, causing a massive amount of thick black blood to gush out.
Taking advantage of the opening created by the two warriors' coordinated actions on the front line, I propelled my body directly toward the creature's chest. I gripped the handle of my sword with both hands, channeling the entirety of my destructive power into the blade until the metal shone like a miniature sun in the middle of the dungeon's darkness. With a shout that echoed throughout the chamber's vaults, I unleashed an overwhelming vertical strike that cut through the monster's draconic carapace from its abdomen to its main neck, opening a gash more than three meters long that split the Chimera Dragon's sternum in half.
The impact was so colossal that the beast staggered backward, releasing a howl of agonizing pain as the force of my attack made its gigantic body tremble. For a brief second, the feeling that we had inflicted lethal damage crossed my mind; the strike had been deep enough to destroy the primary vital organs of any S-Rank beast known in the guild's records.
However, the reality of the sixtieth floor proved to be immensely more grotesque and terrifying than our theoretical predictions had indicated.
Before the mass of black blood could even reach the arena floor, the monumental gash in the monster's chest began to bubble violently. Thick strands of reddish flesh, resembling muscular tentacles and hypertrophied veins, sprouted from the edges of the wound at an abyssal speed. They intertwined in the air with a disgusting sound of cracking bones and fibers stitching themselves together, closing the great opening in the sternum in less than two full seconds. The dragon-scale carapace regenerated with even greater density, covering the open wound with a layer of reinforced bone plates that gleamed with a sickening blood-red hue.
"What?!" Scarlet exclaimed, quickly retreating two steps as she watched the scar disappear completely, as though my attack had never existed. "Its regeneration is practically instantaneous! The muscular tissue is rebuilding itself at the very same moment it is destroyed!"
"It's not just cellular reconstruction!" Eara warned from the back of the hall, keeping her staff raised while the Triple Geometric Nullification Barrier glowed in silver tones around the rear line. "This monster's source of vitality is directly connected to the floor's mana node! It draws energy from the very structure of the Tower to repair any type of physical damage!"
Before I could readjust my stance for a second concentrated attack, the central head of the Chimera Dragon took advantage of my proximity to unleash a blind and brutal counterattack. Instead of using its mouth to bite or channel its fire breath, the creature thrust its left membranous wing forward in a whip-like motion of overwhelming force. The calcified bone at the wing's extremity, reinforced by massive spikes, struck my right flank with the impact of an avalanche crashing down from a mountain.
The impact instantly destroyed the outer layers of my defensive mana barrier. The sound of my ribs cracking under the crushing pressure echoed inside my own head as my body was hurled against the granite floor, skidding for more than twenty meters and raising a cloud of dust and shattered stones across the arena.
"Takumi!" Lyannis's panicked scream echoed through the hall with painful clarity.
The pain spreading throughout my chest was excruciating, burning like red-hot iron and making it difficult for air to flow into my lungs. Warm blood rose through my throat and trickled from the corner of my mouth, staining the metal of my armor. Feeling the severity of that injury caused my heart to slow down for a brief second under the shock of the brutal impact, but my mind remained absolutely lucid and focused on the objective. At this level of exploration, pain was not a sign of defeat; it was merely a biological parameter that needed to be managed with absolute composure.
I placed my left hand on the ground covered in debris, using my sword as leverage to slowly lift myself amid the dust. The Chimera Dragon was already reorienting itself to crush my position, with all three heads roaring simultaneously as its regenerated carapace glowed with the corruption of the Tower's core.
"Don't approach without cover, Rai'kanna!" I ordered, my voice hoarse with blood, but maintaining the unwavering firmness and authority the group needed to hear at that moment. "I'm still standing! Maintain the holding formation on the left flank! Lyannis, concentrate your restoration magic on my respiratory system!"
A beam of emerald-green light shot from Lyannis's staff at the rear, crossing the arena and enveloping my chest in a warm aura of accelerated healing. Feeling my bones realigning and my muscular tissue rebuilding itself under the effectiveness of our healer's magic brought the necessary relief for me to regain my balance and plant my boots firmly against the stone floor once again.
I stared intently at the monumental beast before me, observing how the muscular tentacles were still writhing beneath the new layer of scales on the monster's chest. The regeneration speed of that aberration was truly terrifying, superior to anything we had faced on the previous floors. A conventional brute-force attack, no matter how devastating, would simply be absorbed and nullified within seconds. The battle had entered its most critical and dangerous phase: to defeat an enemy endowed with nearly infinite vitality and capable of seriously injuring the protagonist, we would have to find the hidden flaw in the speed of its own biological reconstruction before our reserves were depleted by the overwhelming pressure of combat.