Isekai Adventure in the Dimensional Cube

The sewer system of Orario differs from that of typical cities, showing no signs of filth or stench.

Here, not only is it constructed in a very orderly manner, but the sewage flowing through the channels isn't as dirty as Reiger imagined. Apart from the slightly murky air, it surprisingly lacks any foul odor.

This is because Orario's underground sewers are equipped with many magistone devices.

In the narrow branch channels, crystal columns emitting a blue-purple glow, resembling iron railings, are installed. Whenever water flows through, these crystal columns purify it, turning the passing water into clean, clear water, making the flow within the channels transparent and pure, unthinkable for discharged sewage.

At intervals, the walls of the sewer have magistone lamps that illuminate the surroundings.

Thanks to this, Orario's sewers aren't filthy or stinky; instead, they have an excessively clean feeling, giving the impression one is walking through a modern tunnel deeply embedded underground, not causing revulsion to the place where waste is discharged.

Of course, walking through these underground sewers, Reiger and his two companions did encounter trouble.

The primary trouble lies in the monsters active here.

Indeed.

There are monsters roaming in Orario's underground sewers.

These are creatures that once surged to the surface during ancient times, proliferating on land. Though not as threatening as the monsters within the underground city, caution is still necessary.

The sewers of Orario lead to the sea in the southwest of the city, discharging the purified sewage into a brackish lake connected to the ocean.

And within the ocean and the brackish lake, aquatic monsters continuously reside.

These aquatic monsters occasionally follow the currents into large cities, moving freely in waterways connected to the ocean. The monsters roaming in Orario's sewers are of this type.

As Reiger and the others walked on the raised passages on either side of the channel, aquatic monsters occasionally jumped out of the channel beside them to attack. Among these, the monster called "Assault Fish" appeared most frequently.

This was a giant fish, about 160 cm long.

Though this fish-like monster couldn't operate on land, it could, like a torpedo, shoot out from the water with splashing droplets, baring sharp fangs, lunging at prey on the water's edge.

It primarily appeared from floors 25 to 27 of the underground city's "Water Mysterious City" domain. While not highly combative, out of the water, it becomes an easy catch, effortlessly dissected, yet its sudden assault from the water, if not detected in advance, could still deal fatal damage to careless high-level adventurers.

Knowing this, adventurers passing the "Water Mysterious City" region heightened their vigilance, carefully watching the water's surface during exploration, even Lv.4 second-tier adventurers.

At the outset, Rephia narrowly avoided being bitten by an assault creature emerging from the water, terrifying the elf maiden into almost screaming aloud.

Fortunately, by her side, along with this Lv.4 elf mage, were two Lv.6 swordsmen.

"Splat!"

As the silver military knife flashed across the dim sewer space, the assault fish shooting from the water hadn't yet bared its fangs before being split in two by the sharp light.

Ais flicked her blonde hair, sternly shielding Rephia, cutting down the attacking assault creatures emerging from the water with her sword.

Reiger, meanwhile, shot forward like an arrow toward another group of aquatic creatures that had crawled ashore.

This was a group of metallic blue crabs whose left or right pincers were exceptionally developed, capable of delivering massive blows like a sledgehammer, their bodies encased in metallic steel shells.

These metallic blue crabs have highly hardened steel shells, far surpassing the killer ants roaming the upper floors and the deadly wasps from the middle floors of the underground city. For adventurers whose weapons lack second-tier armament specs, striking those metallic blue crabs would only see their blades bounce off the steel shells, sparking upon impact.

However, to Reiger, who wielded first-tier special weapons, though the power lessened due to imperfect attributes, they still held higher attack and sharpness among same-tier armaments, posing no issue at all.

"Splat!"

The crystal longsword glided through the air like a cold arc, easily slicing through the metallic blue crab's steel shell.

"Splat!" "Splat!" "Splat!" "Splat!"...

Reiger danced and maneuvered amid the group of giant crab monsters, his sword gliding around them as if performing, felling the monsters one by one.

"Bang!" "Bang!" "Bang!"...

Despite the seemingly large scale of the monster attack Reiger's trio encountered, the two swordsmen continued to slaughter monsters as if unimpeded, while in the channel beside them, water continued to splash, sending assault fish torpedoing towards Reiger and Ais.

"How can there be so many monsters?"

Rephia was dumbfounded.

Though aquatic monsters indeed ascend the wastewater channels into the city's underground sewers, the numbers shouldn't reach this extent, right?

If such massive-scale aquatic monster threats were common in the sewers, the technicians coming for periodic maintenance would have long perished, and the guild would promptly impose mandatory quests, dispatching capable familias for cleanup, which would leak the information to all exploration familias.

Yet Rephia hadn't heard of any abnormal conditions in the city's underground sewer system.

Reiger, however, calmly spoke as he slayed the monsters.

"It's likely because a carnivorous plant monster has been active here," Reiger said. "Those creatures, which devour even their kind and thirst for magistones, pose a natural threat to aquatic monsters living underwater."

"Hence, when a carnivorous plant monster appears in the underground sewer, the aquatic monsters here must be alerted."

"Following their instincts, they've gathered together to combat this sudden threat with collective strength."

"We happened upon one such monster group here and were attacked by them."

This also proves that Reiger and the others are on the correct path.

The carnivorous plant monster has indeed moved within this area, as these monsters indicate.

"Let's take them out," Reiger decisively suggested. "If left unchecked, the next time guild-assigned personnel come for sewer equipment maintenance, they're sure to face an attack from this group of monsters."

As Reiger spoke, he unleashed the abilities he had adjusted to Lv.6 and sprinted swiftly toward another group of metallic blue crabs crawling ashore.

"Boom!"

His speed was astonishing; as he ran, he generated a gust that crashed into the monster group, sending a cluster of metallic blue crabs flying.

Seeing this, Ais' eyes narrowed, and she intensified her attacks in tandem.

"Swish!" "Swish!" "Swish!" "Swish!"...

As a series of sword lights sliced through the air, the ambush monsters springing from the water seemed to collide with an invisible web of sword strikes, getting instantly cut into countless pieces and spraying vast amounts of blood upon contact.

Two remarkably similar swordsmen, displaying the same decisive and courageous demeanor, again inspired the elven girl who admired them.

"I'm joining in too!"

Rephia, who had calmed down, raised her magic staff and began chanting magic.

"[In the name of Viesen, I make a wish.]"

"[Ancestors of the forest, noble comrades. Hear my voice, come to the meadow.]"

"[Bonds of connection, promises of the celebration. Dance in circles, whirl the ring.]"

"[Come, Elf Ring.]"

"[I plead with you—lend me your power.]"

A special magic array unfolded beneath Rephia's feet.

"[Elf Ring]!"

The magic array began to rise, transforming into a ring that encircled Rephia.

This was the very magic that established Rephia's fame.

Restricted to one's kin, as long as she completely understood the effects and chants of another's magic, she could transform it into her own through Summoning Magic—[Elf Ring].

It was due to this magic that Rephia earned the title [Thousand Elves].

Just as Rephia was activating this magic, Reiger, who had already cut in and out several times among the metallic blue crabs, spoke up.

"Don't use fire attribute attack magic! This place won't hold up!"

His words caused Rephia, who was about to launch a large-scale magic, to pause.

Indeed, using fire attribute attack magic here to trigger a massive explosion would certainly collapse the sewers.

With this thought, Rephia promptly altered the incantation that was about to escape her lips.

"[Frozen skies, heavenly rain. Adorn the forest with white ice, I beseech you to drive away the uncultured barbarians—]"

This was magic that Rephia learned from Alicia.

Similar to Revilia's [Frenzied Fimbul Winter], this, too, was an ice attribute wide-range annihilation magic.

"[Freeze them, Winter's Shackles.]"

Following the instructions of those she admired, Rephia cast the magic taught by her fellow clan elders.

"[Ice Hail Crystal Dust]!"

The ring on Rephia's body immediately shattered, transforming into a surge of Magic Power that soared above her head.

In the next moment, the Magic Power condensed into a ball of light, spinning above Rephia's head.

Then, countless ice hail missiles emerged from the light ball, tracing various trajectories, and unleashing terrifying chills as they shot out in all directions.

"Boom!" "Boom!" "Boom!" "Boom!" "Boom!"...

The ice hail magic projectiles suddenly crashed onto the ground or the monsters, freezing the earth into ice and solidifying the monsters into ice blocks, then shattering them explosively.

[Ice Hail Crystal Dust], this wide-range annihilation magic is characterized by a 365-degree angle of attack without dead spots, able to sweep any direction. Though its power and range do not match Rephia's own [Simultaneous Fire Spear], nor Revilia's [Frenzied Fimbul Winter] or [High-level Victory Sword], its area coverage within the range is quite high, making it very valuable.

As Rephia used this magic, she immediately chanted another magic.

"[Released light arrow, sacred wooden bow, I am the hand named for the bow.]"

"[Strike now, elven archer.]"

"[Pierce, Guaranteed Hit Arrow.]"

"[Arc-shaped Beam]!"

The single-shot magic with tracking ability was completed at an extremely fast speed.

However, as soon as Rephia finished chanting this magic, it didn't get fired; instead, it transformed, along with its magic array, into a small crystalline sword that hovered by Rephia's side.

Rephia silently muttered in her heart.

"[Sword Spirit Chasing]——activate."