When they opened the door, it seemed to be a boss room, and they stepped into a vast chamber.

It was Tooru’s first time entering a dungeon as an explorer—except for the previous Kamioka Dungeon—so he had little to compare it to, but it gave him the same impression as the fourteenth floor there.

A place with nothing but walls, floor, and ceiling. Just an enormous open space.

Like a small gymnasium.

Something was there, about fifty meters ahead.

Monsters leaked mana outside their bodies, and when it reacted with the air it produced a faint glow. This was more noticeable outside a dungeon. During the Dungeon Stampede, the orochi and the hydra had been visible even from three hundred meters away, but whatever stood fifty meters ahead now was somewhat hard to see.

Simply because mana already permeated the dungeon.

In any case, lingering in front of the door was dangerous—if a dragon-like “breath” attack or some other area attack were unleashed, there would be nowhere to escape. Without anyone needing to say it, Tooru’s group quickly moved into the open space toward the center of the room.

Click, click—Kujou Reiko’s boots echoed.

Tooru’s combat boots seemed to be made of a different material, producing little sound. Tia clearly wore metal greaves, yet somehow made no noise at all. As for the butler, that went without saying—nothing about him would stand out, footsteps included.

After advancing about fifteen meters, the enemy came into view.

“Oh! A demon type.”

Tia said it with the excitement of a high school girl spotting a new convenience-store product.

Just as she said—the creature standing in the middle of the room was an eerie monster with green skin, shaped somewhere between a human and an ape.

Bat-like wings spread from its back. Its upper body looked bare, while its lower half was covered in beastly fur. A thin tail like a monkey’s extended behind it, and a pair of horns grew from its head.

It looked over two meters tall, but because it rested its hands on the ground like an ape or gorilla, it didn’t feel towering. Even so, it carried an overwhelming wrongness—something no natural animal could ever be.

Because most animals live in order to live.

But demon-type monsters—clearly existed to harm.

An alien presence incompatible with life in this world.

The moment Tooru’s group noticed it, it noticed them as well… or rather, they had entered its combat range.

“This type of demon is mid A-rank.”
“Doesn’t look unique, but something seriously nasty just spawned.”
“A-rank on floor thirteen? Even if there are sixteen floors total, this dungeon’s S-rank.”

“Toorubro-sama, let us handle this together. I could defeat it alone, but dungeon exploration often requires fighting alongside companions, so this makes a perfect opponent in that sense. Demon-type monsters cast magic without charge time or chanting, so as long as you watch for that, it’s nothing for us to fear.”

Kujou Reiko stepped forward with a sharp tap of her boot.

“M’lady, try to look a bit cooler.”

Her butler, Jouichirou, offered that unnecessary comment. Reiko paused to think for a moment, then—despite the demon right in front of them—turned toward Tooru, pinched the hem of her day dress, bent her knees, curled her lips into a sly smile, and tried again.

“—‘Shall we dance?’”¹

He couldn’t help but laugh.

So this was what it meant to enjoy oneself.

Tooru swung the steel rebar club in his hands and smashed the demon-type creature just as it was about to bring its right arm down on Reiko. Not that she would have been in real danger—she had already taken a stance in the blink of an eye. If he hadn’t acted, she would have countered herself.

“Sounds good, Kujou-san. Well then, ‘Let’s rock, Baby.’”

The demon that had been blown away by the strike somehow halted dead in midair, spread its arms, and fired magic—twelve fire-attribute magic arrows.

Stepping deliberately in front of Reiko, Tooru charged straight into the barrage.

He had never once been hit by magic in his life.

Yet ‘Kagetsu’ within him judged there was no problem.

Because he bore the protection of the ‘Lightbringer’ connected to his soul.

Immunity to mid-tier magic and below.

The magic arrows vanished just before touching him, and the demon stiffened in momentary surprise.

He continued closing the distance, but Reiko, tracing a lightning-like path with intricate footwork, reached the enemy even faster. It was an absurd approach—like a joke. And of course, she didn’t stop at merely closing in.

Three impact sounds rang out. Like a sledgehammer smashing a tire with full force. Face, abdomen, then face again—after the blows, her body slid smoothly aside.

She had sensed Tooru’s approach and moved to avoid friendly fire.

A single blow from the blunt weapon.

A simple vertical strike straight down from above. The impact was so intense that Tooru’s hands went numb, and even the demon-type’s head wobbled violently. But he didn’t follow up with the weapon. Instead, he kicked the creature’s head with the sole of his boot and used it as a foothold to spring straight backward, opening distance.

The very next instant, the wings on the demon’s back transformed into blades and whirled around, scything through the surrounding space.

Had he been within range, his torso might have been severed—that was the level of power and sharpness. But once avoided, it left an opening ripe for a counterattack.

“I am going in!”

A right vertical fist shot forward alongside footwork too fast for the eye to follow. The motion of her body and the flow of her mana were so perfectly synchronized it could only be called a master’s strike.

The moment Kujou Reiko’s fist struck the right side of the demon’s head, Tooru slammed his rebar club into the left side.

A sandwich of fist and blunt weapon.

A strange booming impact and a dull sensation traveled through the strike.

The instant he realized they hadn’t penetrated the demon’s mana defense, Reiko had already stepped again and driven in a left hook. Then right, left, a two-knuckle thrust aimed at the throat, a left palm strike to the ear, and a side kick targeting the knee joint. The recoil naturally carried her back out of range.

As her speed ramped up, Tooru could no longer keep up and had already stepped back a few paces to observe—

“It is too hard! Toorubro-sama, I shall yield the initiative to you next!”

Reiko said this with unmistakable delight. Tooru hadn’t found any breakthrough with his blunt weapon, but apparently she had. There wasn’t even time to nod—he simply stepped forward and closed in on the demon, which seemed to be savoring the aftermath of the combo.

He raised the weapon—and dodged the demon’s right arm.

It hadn’t just stood there like a punching bag after all; it had been waiting for him to overextend in pursuit. But Tooru’s inner self dismissed that trap with a cold certainty, as though it had known it for a hundred years.

He converted the evasive motion into a connecting step, poured as much mana as he could into the weapon, and brought it down on one of the horns on the demon’s head. With a sickening crack, one of the pair snapped off.

“Hah—!”

In the same instant, Reiko slipped into the demon’s guard with suddenness like teleportation and performed a strange motion. No wind-up, no visible force—she merely placed a hand lightly against its chest, lowered her hips just slightly, and———BOOM!

A bizarre sound rang out, and the demon was blown away. A monster that surely weighed more than an adult man—probably as much as a gorilla—shot backward parallel to the ground and didn’t stop until it slammed into the far wall of the chamber.

It was an utterly absurd sight.

“Mana Inch Strike! I have shaved down its mana defenses quite a bit!”

Laughing, Kujou Reiko immediately pursued the demon she had just blown away. She didn’t run—she advanced with guarded stepwork, gliding just above the ground. From her hips to her back, her posture didn’t waver in the slightest, as if an iron rod had been driven through her spine.

Refinement.

‘Kagetsu’ within Tooru instinctively recognized that core—something possessed only by those who had tempered themselves through endless cycles of practice: kneading, hammering, heating, hammering again, sharpening and polishing without end. He felt respect well up from deep inside his chest.

No wonder everyone liked her.

How much effort had she poured in just to be able to enjoy herself like this? And to call even that effort fun—such a feat was something ordinary people could scarcely comprehend.

Perhaps this young lady would have cheerfully worked even as a cleaner in a D-rank dungeon.

With a half-beat delay, Tooru also broke into a run, picking up the demon’s fallen horn from the floor along the way. Though called a horn, it wasn’t complex like a deer’s antler—more like a simple cone.

By the time he reached the demon near the wall, several more exchanges had already taken place: flurries of attacks, counterattacks, evasions. What surprised him most was that Reiko was literally punching the demon’s attacks themselves aside, deflecting them mid-strike. Judging from the creature’s build, she seemed to be predicting its movements through sheer experience.

It went without saying for Tooru, but he had the distinct feeling that if Reiko took even a single clean hit, the entire battle could turn.

The demon excelled in mana defense and had tremendous attack power. Its movements lacked fluidity—but if it forced through even one solid blow with brute durability, the explorers’ ability to evade afterward would be critically impaired.

“Match my timing, Kujou-san.”

He said so as he charged from the side toward the demon swinging its massive arm at her. As expected, the rebar club did little real damage—but it drew the creature’s attention.

The instant its focus shifted to him, Tooru casually tossed the weapon in his right hand as though making a pass.

The demon froze for a split second at the incomprehensible action.

Into that opening, Tooru thrust the horn he had picked up straight into its chest. It only pierced slightly—but he kicked it, driving it deep into the torso, using the recoil to spring backward and open distance at the same time.

“Haah—!”

Reiko struck with an Inch Strike aimed precisely at the horn embedded in the demon’s chest.

Carried by his own backward momentum, Tooru slid across the floor without properly landing, watching her blow—like a crystallization of blood, sweat, and exhilaration—connect.

A violent impact rang out.

The demon slammed into the wall once more, then light particles began spilling from the gaping hole in its chest as its body gradually dissolved. Only after it vanished completely did Tooru finally exhale.

They had defeated it.

Without using either the Cursed Sword or the Holy Sword—well, he had used the combat skills and blessings, but not the weapons themselves—he had fought alongside an A-rank explorer without falling far behind.

…At least, he thought so. Maybe that was an exaggeration. Perhaps there had been a gap after all. Still, not dragging her down too badly was good enough.

“O-ho-ho-ho! We did it, Toorubro-sama! Our combination was splendid! That was rock ’n’ roll!”

Beaming, Kujou Reiko ran up to him, grabbed both of his hands while he was still lying on the floor, hauled him upright as if pulling up a weed, then kept hold of his hands while hopping in place and shaking them up and down enthusiastically.

Her joy was so utterly guileless, so straightforward, that Tooru couldn’t help but give a wry smile.

He couldn’t share her exuberance—but he felt he had at least begun to understand a fragment of the fun.

Killing monsters didn’t have to be done with grim seriousness alone.

Kujou Reiko was staking her life—and enjoying it.

He didn’t fully grasp that level of resolve, but his sense that finding enjoyment in dungeon exploration was somehow “foolish” had faded a little.

After all, no one normally keeps killing monsters with zero enjoyment whatsoever.

“Man, this is the first time I’ve seen M’lady fight alongside someone. I’m moved. Oh—but the boss drop’s just a magic core. No rare drop.”

“That looked tough, but you handled it better than I expected. Reiko’s combat style is even more impressive than I imagined.”

The butler and Tia—who had somehow drawn close—spoke like spectators. Well, thinking about it, even if things had gone badly, those two had been standing by. In that sense, both Tooru and Reiko had been fighting within a kind of safety net.

“My, my, thank you kindly, Tia-sama. But Toorubro-sama’s performance was remarkable as well. One would never think he only became an explorer yesterday. In other words—we are both extremely fabulous! O-ho-ho-ho!”

Thinking he wouldn’t mind learning even a toenail’s worth of that self-confidence, Tooru unconsciously slipped his hands free from hers and picked up the magic core the demon had dropped—along with his fallen rebar club.

“Amazing! Seriously amazing!”
“What was that combination?!”
“Without commentary that made zero sense!”
“Tooru-bro did great even without the cursed sword!”
“Keeping up with an A-rank, lol.”
“Viewers just hit sixty-five thousand.”
“Subscribers passed forty thousand too.”
“Still made sure to grab the magic core, lol.”

The livestream chat was in an uproar. So this was what dungeon exploration streaming was like, Tooru realized with interest. Of course, Reiko’s presence contributed enormously—but even without being an A-rank explorer like her, there must be countless explorers out there balancing social contribution and personal enjoyment within their own limits.

“Hey, Tooru. Say something to the people watching.”

Tia prompted him with a bright smile. Being coaxed into it annoyed him a little—but taking that irritation out on the viewers would be completely misplaced.

“Uh… well… Thank you for watching. …What are you grinning for? I can say thanks too, you know.”

“Rare Tooru-bro tsundere sighting!”
“Clip it, clip it!”
“It’s honestly funny that him being rude feels more right.”
“His gratitude is so awkward lol.”

“Shut up. I just haven’t had many chances to thank people, okay? I’ve still got a bottom-feeder mindset.”

“O-ho-ho-ho! Splendid spirit, Toorubro-sama! …Well, I only said that on a whim. However—if that is who you are, then there is no need to force yourself to change until you change naturally. After all, we are explorers first and streamers second! Some people are the opposite, of course, but you and I are not, correct? In that case, there is no need to humble yourself before the viewers. Simply be your authentic self, Toorubro-sama!”

“Well, M’lady is M’lady.”
“To be fair, Tooru-bro hasn’t been rude to us viewers.”
“Keep entertaining us, Explorer Toorubro!”

“…‘Toorubro’ isn’t my name, you know.”

He added a retort about how even as a nickname it was longer than his actual name.

Of course, no one stopped calling him that.

◇◇◇

Just as they were about to descend to the fourteenth floor, a problem hit the stream.

Jouichirou the butler reported that communication strength had dropped, and viewers also mentioned heavy lag. Tia and Kujou Reiko didn’t seem to understand what that meant, but Tooru had a hunch.

“Could the Dungeon Mutation have messed up the magic comm relays?”

They returned to the thirteenth-floor boss room for the time being, and he voiced the thought aloud.

Reiko and Tia still looked confused, but the butler nodded readily. So did the chat.

“Possible. Rare, but there are cases where magic comms stop working in mutated dungeons.”
“Super rare for exploration streams, though.”
“But since this is technically an investigation, it still counts as useful data.”

“Yeah. Either way, if we go another floor or two down, things might get dicey for M’lady. Let forwarding into unexplored territory wait.”

“Hm… regrettable, but Jouichirou has a point. If multiple A-rank monsters appeared, I alone would struggle, and relying entirely on Tia-sama would hardly make for enjoyable exploration.”

“Well, we can’t be certain until official classification, but judging from the final boss chamber, this is probably an S-rank dungeon. Simple structure, difficulty ramps cleanly—honestly, it’s super profitable.”

“The profit gang is wise.”

“So… does that mean cleaners won’t really be needed anymore?”

“Almost certainly not. In fact, it’s practically ideal for training. Once the full survey’s done, this place will probably be packed.”

“Huh… I wonder what’s become of the Noumi Dungeon.”

“Well, turning S City’s infamously awful dungeon into a jackpot dungeon is bound to cause a stir.”

The butler laughed lightly, as though it were someone else’s problem. Tooru didn’t feel particularly indignant either—his attachment to his hometown wasn’t that strong.

“Either way, that means the stream ends here. We shall head back and call it a day.”

“Ah, shame but fair.”
“Great first stream!”
“Stream solo—or duo—again!”
“Heard this is the Tooru-Tia-tan couple channel.”
“Want to see Tia-chan fight next time!”
“Even a chat stream is fine!”

“Uh… yeah, I guess we’ll wrap it up. Thanks for watching. Haven’t decided what to do next yet… but your feedback’s pretty valuable, so I might ask for input. See you.”

“Oh! Me too! Please watch again, okay? I like talking with you all. You said I’m cute, and that made me happy.”

Ignoring the chat’s sudden explosion at Tia’s words, Tooru signaled to the butler holding the streaming camera.

“GG!”
“Good job!”
“Tia-tan is adorable.”
“GW-GW~”

Stream ended.

They didn’t descend further from the boss room and instead turned back. All told, they had spent over six hours inside the Sugai Dungeon—yet reaching the thirteenth floor in that time was, according to Reiko and Jouichirou, “abnormally fast.”

Thinking about it, monsters up through around the tenth floor hadn’t posed any real threat to either of them, and the dungeon’s structure was simple. Maybe, as the butler said, it really was a “profitable” dungeon.

As they reached the staircase from the twelfth floor to the eleventh, Tooru’s mobile terminal—currently held by Tia—rang. Not knowing how to answer, she fumbled with it, so Tooru took it back. The caller ID showed an unfamiliar number, which made him wary, but he answered anyway.

The person on the other end was someone he hadn’t expected.

〈—Hello. Um… good job on the stream. This is Kawai Sakiho.〉

1. this and the one below are said in English.