The geometric transition between the intermediate floors and the twentieth level brought a drastic change to the very material structure of the tower. The dark granite and white marble columns of the previous sanctuaries disappeared completely, giving way to a vast and oppressive plain of cold ashes and fragments of obsidian that stretched beneath an artificial sky eternally tinged with a twilight purple. The atmosphere there was so dense that every gust of wind carried with it the static hiss of highly concentrated purplish mana, causing the hairs on our arms to constantly stand on end due to the static electricity.
Walking through that gray desert was a trial of pure mental endurance. There were no trails, geographical landmarks, or ruins that could guide us; only an immense stretch of barren land that seemed to drain our vitality with every step taken upon the unstable, sandy ground.
"We are approaching the energy center of the twentieth level," announced Rai'kanna, stopping at the top of a small ash dune and pointing toward the geographical depression just ahead. Her ears tilted forward, catching the seismic vibration that was beginning to shake the obsidian foundation beneath our feet. "The mystical oscillation pattern here is identical to what the highest-ranked adventurer described in his report at the mansion. The containment barrier of this floor's boss was automatically activated upon our entry."
At the bottom of the circular depression of ashes, the ground began to move like boiling water. An immense spiral of dark sand and mineral debris rose toward the artificial sky, revealing the monumental silhouette of the elite monster that had interrupted the first explorer's expedition.
It was the Silicon Colossus: a colossal quadrupedal creature composed entirely of geometric blocks of black crystal and energized quartz that glowed with a pulsating yellow light through their internal cracks. It possessed no visible sensory organs, but the flow of its mana directed toward us made it clear that the opponent possessed complete and immediate three-dimensional spatial perception of the entire ash arena.
"It is exactly the opponent that forced the first expedition to retreat," I commented, drawing my sky-blue blade and observing how the runic glow of my physical weapon flickered slightly under the influence of the colossus's electromagnetic field. "Its structure is designed to reflect long-range magic through its crystalline facets and repel physical combatants with high-frequency kinetic shockwaves. We need to break the resonance of the crystal plates before attempting to deliver any definitive blow."
"It is beginning the energy charging cycle!" Elara warned, pointing toward the quartz spines on the monster's back, which were beginning to glow with an incredibly bright and dangerous yellow hue.
"Scarlet, keep its tactical focus on the right side and do not try to block the frontal attacks directly," I ordered quickly, running down the ash slope to flank the creature from the opposite side. "Lyannis, use your wind magic to create a dispersion barrier and reduce the impact of the electrostatic dust it releases! Liriel, position your mystical defenses in layers behind us!"
The Silicon Colossus launched its first attack, a powerful paw strike that generated a horizontal shockwave capable of lifting tons of dark ashes into the air. The kinetic force of the impact was so violent that the air around us buzzed with a deafening crack of compression.
Thanks to the new perfect-evasion combat stance we had adopted on the previous floor, Scarlet did not attempt to contain the force of the blow with her light metal shield. Instead, she used the momentum of Lyannis's wind wave itself to slide agilely down the ash slope, dodging the immediate destruction zone by mere centimeters and delivering a precise cut to the rear leg joint of the crystal giant as she passed it.
Scarlet's blade impact tore off shining shards of quartz, but the monster reacted immediately, rotating its colossal body with surprising mechanical agility and firing a volley of sharp crystal projectiles from its back.
"Containment runic barrier, now!" exclaimed Liriel's assistant, activating a horizontal magic circle that projected itself before us like a wall of highly dense golden energy.
The crystal projectiles collided against the mystical barrier with a shrill noise, fragmenting into harmless dust while Liriel channeled her purified mana to maintain the shield's integrity against the continuous pressure of the attack. The healing suppression of this floor required every support movement to be perfectly coordinated to avoid wasting biological energy on unnecessary injuries.
While the monster was focused on Liriel's shield, Vespera silently descended from one of the obsidian ledges surrounding the circular depression. She landed softly on the colossus's back, driving her twin daggers directly into the mystical junction where the crystal plates connected to the beast's central mana core.
The colossus's yellow energy flow fluctuated abruptly, causing a sharp hiss of instability throughout its stone body. The giant began struggling violently, attempting to crush Vespera against the stone walls of the ash arena.
"It is destabilized! Now is our chance, Takumi!" shouted Rai'kanna, advancing along the side with incredible speed to apply a restraining strike that locked the monster's front leg movements with her high-traction runic cables.
I channeled all my sky-blue mana into the sword, feeling the energy vibration reach its physical peak. I advanced in a long leap, crossing the ruined space of ashes and delivering an extremely powerful vertical strike against the weakened point that Vespera had opened in the chest of the quartz giant.
The sky-blue blade penetrated deep into the black crystal carapace, striking the monster's glowing core with surgical precision. With a sharp crack that echoed throughout the ash canyon, the cracks rapidly spread across the entire geometric structure of the colossus, causing the obsidian plates to lose their physical cohesion and collapse onto the arena floor like a pile of harmless gravel.
Absolute silence returned to the gray plain, interrupted only by the constant breath of the purple wind that cleared the floating crystal dust from the air.
At the center of the defeated monster's remains, a small bluish light began to float gently, condensing into the form of a small circular rune made of gray stone that hovered a few centimeters above the obsidian ground. It was the tower's first permanent abandonment rune, the mystical item that would allow any adventurer to abandon the ascent and safely return to the Isolated Lands without suffering the effects of the Demon King's cumulative miasma.
I approached the runic fragment, feeling the peaceful energy vibration emanating from the small stone object. I looked back, seeing the face of each of my squad companions, all visibly exhausted from the high-density combat and the constant weight of the purplish atmosphere, but with their eyes shining with an unshakable determination that no mystical trial of that tower had been able to diminish.
"This is our definitive escape route if we decide to retreat now," I commented, holding the abandonment rune in my left hand and feeling its spatial signature of safety. "We overcame the challenge that defeated the strongest warrior of the Alliance. We proved that the Demon King's system of rules is not invincible against our group coordination tactics."
"We are not going to retreat now, Takumi," said Scarlet, approaching with firm steps and placing her right hand on my shoulder with a smile full of tactical pride. "We knew this floor would be difficult, but our victory here shows that we are greater than any obstacle this place can project against us."
"She is right," Liriel agreed, closing her prayer tome and approaching the group with an expression of pure spiritual clarity. "We came here to disarm this structure and free our world from this final threat. Retreating now would allow the Demon King to reorganize himself and change the rules of the game for our next attempt at ascending."
My companions' words brought a profound sense of peace and purpose to my inner self. The fear of failing or losing the people I valued had been a constant in my chest since the day I decided to officially accept the tower's challenge. But seeing the inner strength that each of them demonstrated in the face of difficulties made me realize that our journey was not a solitary burden that I needed to carry on my back; it was a shared effort of minds and hearts that had chosen to fight together for the future of our Alliance.
"Very well," I declared, securing the permanent abandonment rune to my tactical belt with a firm and decisive movement. "We are not going to use this escape route. We will continue our ascent with the same practical focus as always. The twenty-fifth floor and the first true major checkpoint are just above us, and we will not stop until we reach that objective."
With their spirits perfectly synchronized by the warmth of true victory, the squad adjusted their combat equipment and advanced in a coordinated and silent manner toward the dark marble staircase that would lead us to the final challenges of the second cycle of floors of the colossal Demon King's Tower.