The humidity that had begun to project from the black stone arch transformed into a thick physical barrier the instant we crossed the dimensional portal. The fresh aroma of pine and vegetation-rich soil from the third level vanished abruptly, being replaced by the pungent smell of wet peat, decomposing vegetation, and mild sulfur. We were now stepping onto muddy, soft, and treacherous ground that subtly gave way beneath the weight of our combat boots.
Ahead of us stretched a vast and gloomy artificial swamp of continental proportions.
A dense gray mist hovered over the surface of the stagnant water, limiting visibility to just under ten meters. Twisted trees, with gnarled trunks and leafless branches, rose like skeletal silhouettes from within the pools of dark mud. The ceiling of this level no longer displayed the illusory blue sky or the false stars of the previous floor; instead, heavy, dark clouds of condensed miasma moved slowly, blocking any natural brightness and casting a permanent gloom over the swampy landscape.
"The atmosphere here is incredibly heavy," commented Liriel, adjusting the hood of her cloak to protect herself from the fine drizzle of acidic mana that was beginning to fall. She extended her left hand and watched the droplets touch the treated fabric of her garment, leaving small points of harmless smoke. "The humidity carries a subtle corrosive charge. It is not enough to melt our armor immediately, but it will wear down the durability of our equipment if we remain exposed for too long."
"And the mist interferes with my mystical vision," Elara added, keeping one finger positioned on the string of her bow as she tried to focus her gaze on the misty darkness ahead. "The magical density of the gray smoke distorts the reflection of light. It is like trying to see through a fogged mirror."
"That means we will have to rely almost entirely on our hearing and Rai'kanna's thermal perceptions," I observed, stopping at the edge of one of the few walkways of solid ground that seemed to cut through the low vegetation of the swamp. "This floor was designed to test our limited senses and our ability to maintain balance under constant psychological pressure. The silence and visual isolation are the environment's greatest weapons here."
Rai'kanna moved to the front, crouching over a fallen log that was partially floating in the mud. Her ears moved independently, filtering the constant sound of raindrops striking the stagnant water.
"I can hear the movement of underground currents beneath the swamp," she informed, pointing toward a dense row of tall reeds to our right. "But there is also something rhythmic and heavy moving between the pools of mud. It is not a single creature, but several of them moving in coordination to close our path."
"Prepare yourselves," I warned, drawing my runic sword with a quick and firm movement. The blade emitted its sky-blue glow, cutting through the thick mist like a beacon of hope in the gloom of the swamp. "Scarlet, maintain the immediate rear position. Lyannis, we need a constant source of light that will not be dissipated by the acidic humidity."
"Leave it to me," Lyannis replied.
She channeled a small portion of her mana, creating not an ordinary floating sphere, but a flame of compressed wind that glowed with an intense emerald-green hue. The special light cut through the mist without being affected by the corrosive drizzle, revealing slender and dark shapes crawling across the stagnant waters around us.
They were runic alligators with dark carcasses, covered by massive stone plates that seemed fused to their scaly skin. Their eye sockets glowed with a sickly yellow hue, and their jaws, filled with serrated teeth, released a yellowish and acidic smoke with every slow breath. They did not advance with the impetuous speed of the wolves from the third floor; they moved stealthily, using the deep waters of the swamp to conceal their approach.
"They are heavy, but extremely agile in the water," warned Vespera, who had climbed one of the twisted branches of a nearby tree with silent movements. From her elevated position, she had a subtly better view of the monsters' approach. "If they manage to drag any of us into the deep mud pools, the tactical advantage will be entirely theirs."
"We are not going to give them that opportunity," I declared, stepping my right foot onto the solid-ground walkway at the exact moment when the first runic alligator leaped from the water with its mouth wide open.
I dodged sideways from the initial lunge with a fluid movement, allowing the heavy creature to crash into the muddy ground. Then, I delivered a precise diagonal strike with my runic sword, striking the gap between the stone plates on its neck. The sky-blue blade cut through the scaly flesh with ease, releasing a purifying energy that instantly neutralized the monster's mana.
At the same time, two other monsters emerged from the opposite side, attempting to flank Liriel and her assistant. Scarlet acted quickly, stepping in with her heavy sword. She delivered a horizontal slash of tremendous physical force that hurled the first invader back into the stagnant water, while Elara fired an incendiary-tipped arrow directly into the second enemy's eyes, forcing it to retreat amid pained growls.
The battle in the swamp required even more refined teamwork than the previous confrontations. The unstable ground prevented quick evasive movements, forcing each of us to place complete trust in the mystical and defensive cover of our companions. Lyannis used gusts of wind to repel the acidic mist that the monsters attempted to blow toward us, while Liriel's assistant created small temporary mystical barriers beneath our boots to prevent us from slipping in the black mud.
"They are retreating to reorganize their attack underwater!" Rai'kanna warned, noticing the subtle change in the swamp's acoustic vibrations.
"Do not give them time to regroup," I ordered, looking at Lyannis. "Can you freeze the surface of this pool of water?"
"Perfectly, Takumi!" replied the light-haired mage.
She drove the base of her runic staff into the muddy ground and channeled a concentrated cooling spell. A wave of bluish ice spread rapidly across the dark waters of the swamp, freezing the surface of the lake within a radius of twenty meters around our platform. The alligators attempting to hide in the depths became trapped beneath the thick layer of mystical ice, drastically limiting their mobility and ability to surprise us.
With the enemies temporarily immobilized by Lyannis's frost, Scarlet and I advanced in coordination, eliminating the remaining threats with clean and precise attacks. Within a few moments, the dark calm returned to reign over the tower's fourth floor, and the bodies of the stone creatures began to dissolve into the dark water, being reabsorbed by the immense vertical structure.
"Excellent cooperation from everyone," I commented, sheathing my blade and wiping away the few droplets of mud that had splashed onto my combat boots. "The strategic use of the ice spell spared much of our physical strength."
"This is pure survival," reflected Liriel, walking toward me while checking the quality of the air with a subtle personal purification spell. "The tower tries to impose extreme climatic and geographical conditions on us to test our biological limitations, but group intelligence will always find a clean way to neutralize the advantages of the board."
"And the most important thing is that we kept our mental focus intact," added the research assistant, closing her measurement report with a dry snap. "The acidic magical density of this floor was controlled by our barriers without forcing us to consume the potions we prepared."
I looked at the gray mist that continued to float among the skeletal trees of the swamp. The fourth floor had presented us with a considerably more hostile environment than the sunny forest of the previous level, but the effectiveness of our tactics gave us the certainty that we were ready for any environment the Demon King placed before us.
"The path to the fifth floor should be just beyond that dry peat hill," Rai'kanna pointed out, indicating a subtle rocky elevation that stood out in the misty darkness ahead of us.
With renewed determination and the certainty that our tactical harmony was our greatest armor against the tower's miasma, our squad resumed its silent and focused march through the frozen waters of the gloomy fourth floor.