Chapter 16: The Expansion of Distortion

​After the three-day trip to outer space, which I had taken on a request from my student Niira Ririo—who also happened to be an "Independent Judge of the Galactic Federation." Together, we'd traveled to the far reaches of the cosmos to the planet Pharmacoon, rescued hostages, repelled a space battleship commanded by a criminal syndicate boss, and finally made it back home.

​But what awaited the Hero who had just made his glorious cosmic debut was the incredibly heavy, damp gaze of a certain long-haired, sharp-eyed black beauty: Aouji Misono.

"Sensei, this is going to become a real problem, you know?"

​Aouji came up to me the moment morning homeroom ended, just as I was about to head back to the staff room. Those were the very first words out of her mouth. It wasn't just the look in her eyes; her entire expression and tone carried a heavy, accusing weight.

"What are you talking about?" I asked.

"Taking a three-day absence at the exact same time as a female student is practically begging the other girls to suspect something," she said, her voice dropping as she glared at me. "On top of that, someone saw Ririo adjusting your tie the other day. Under the circumstances, this is a breeding ground for rumors."

"Hmm... Now that you mention it, I suppose so...?" I muttered, scratching my cheek.

"It absolutely is! Kagari and I might know the real story, but it's not like we can use that as an excuse."

"Ah, yeah, fair point. But the administration is fully aware of the situation. Officially, our absences just happened to overlap. We'll probably just have to give up and let them gossip."

"I hope it's that simple. I suppose rumors are just rumors in the end..."

"I appreciate you worrying about me, though," I said with a small smile. "If we just go about our daily lives normally, the rumors will die down on their own soon enough."

​As the saying goes, rumors only last for seventy-five days. A bit of idle schoolyard gossip wouldn't keep its steam for long.

​Seeing that I wasn't particularly panicking, Aouji relaxed her shoulders slightly.

"Well... I suppose you're right. But really, nothing happened, right?"

"Hm? Oh, a ton of things happened over there. We even had a clash with a space battleship, actually."

​Aouji rolled her eyes, letting out a heavy, exasperated sigh.

"That is not what I meant at all."

"Then what did you mean?"

"Never mind. I trust you on that front, Sensei."

"Oh...?"

​While I struggled to find a response, Aouji swept her long black hair over her shoulder and turned back toward her seat.

​Soutou Kagari, our resident small-animal-like twintail girl, immediately poked her arm with a cheeky grin.

"See? I told you there was nothing to worry about," ​Soutou teased.

"It's not that! I was just warning him because Sensei is completely thoughtless sometimes," Aouji snapped back, her cheeks flushing slightly.

"If you say so~ But if you ever got an overnight mission alone with Sensei, you'd leap at the chance, wouldn't you, Misono?"

"I would not! And even if I did go, I'd bring Master along... actually, wait, I can't bring her there... but I'd definitely make sure someone else came with us!"

"Ehh? Wouldn't that be a waste?"

​Soutou shot a playful glance my way. Her eyes were full of mischief, which meant Aouji was probably going to be fine for now.

​While the inner workings of teenage girls' minds often remained an absolute mystery to me, Aouji did have a point about the space trip. Even if it was unavoidable, a male homeroom teacher and a female student being absent for the exact same three days was profile-raising in all the wrong ways.

​As for the other party involved, Niira maintained her usual blank, doll-like expression as she calmly prepared for the next class. Did she share my pragmatic outlook, or did she simply not care about schoolyard gossip from the start? Knowing her, it was almost certainly the latter.

​At any rate, scanning the classroom, none of the other girls seemed to be staring at Niira or me. They were a well-behaved bunch, so they might just be polite enough not to gawk openly.

​Still, if something like this ever happened again, I'd have to arrange a better cover story. Even with the power of a Hero, there was no stopping the school rumor mill once it got grinding.

​

​Back in the staff room, Kumagami-sensei, the grade head, leaned over from his desk next to mine. He was the former homeroom teacher of Class 2-1—my current class—and, true to his name, was a middle-aged man with a distinctly bear-like appearance.

"Aiba-sensei, did Aouji say something to you?" Kumagami-sensei whispered.

"Ah, yes. She was warning me to be careful about starting rumors."

"I figured. She seemed incredibly worried. She kept asking me about your whereabouts every single day, but obviously, I couldn't tell her a thing."

"I'm really sorry about that. I left without giving them any explanation. Next time something like this happens, I'll make sure to leave a brief word."

​Kumagami-sensei furrowed his brow and lowered his voice even further.

"By the way... what actually happened? Taking a three-day absence out of nowhere must have been for something major, right?"

"Well, let's just say I traveled to a planet tens of thousands of light-years away. Niira-san swore me to secrecy regarding the details, so..."

"The terrifying part is that I know you're not joking," Kumagami-sensei said, shaking his head with a wry smile. "You really are something else, Aiba-sensei."

"Honestly, even I was left spinning by this whole ordeal... I was basically just dealing with whatever crisis popped up in front of me."

"Still, the fact that students like Niira and Aouji rely on you so heavily speaks volumes. Just make sure you look after your health. If you burn out like I did, it takes a long time to bounce back."

"Thank you. My physical health is fine—even if I get broken, I tend to heal almost instantly—but dealing with teenage girls is taking a serious toll on my mental stamina..."

"Ah, that... Well, you'll just have to get used to it. If things get too overwhelming, you might want to consult Yamashiro-sensei rather than me."

"Oh? Did I hear my name, Kumagami-sensei?"

​The one who had so sharply caught his words was Yamashiro-sensei herself. Her black hair was swept up in an elegant updo, and the beauty mark near her mouth lent her an allure that seemed almost inappropriate for a school faculty member. She was somewhere in her thir—no, let's say she was a beauty of completely mystery age. She had a daughter named Kiyone-chan, who currently attended Meiran Academy's elementary division.

​Come to think of it, Kumagami-sensei had stepped on Yamashiro-sensei's toes—or rather, a tiger's tail—the other day... Yes, it was definitely wiser not to ask about that.

"Ah, yes! I was just saying that if Aiba-sensei is struggling with how to handle the students, he should seek your counsel, Yamashiro-sensei," Kumagami-sensei stammered.

"Indeed, the way young girls think can be quite a puzzle for male teachers, so I'd be happy to give you some advice," Yamashiro-sensei said with a soft, knowing smile. "Though, from where I'm standing, it looks like you're handling our girls quite beautifully, Aiba-sensei."

​As Yamashiro-sensei beamed warmly, Kumagami-sensei nodded in agreement. "Too true."

"I covered your class for those three days, and it's completely Aiba-sensei's class now. I'd never guess you were a rookie teacher. But being young comes with its own brand of trouble."

"Exactly. And after that incident with the intruders, your popularity has absolutely skyrocketed, Aiba-sensei. I've had several girls in my own class asking all about you."

​The "intruder incident" referred to when three suspicious men had snuck onto campus, and I had subdued them. It was actually a highly classified affair with hidden motives, but I had no idea it had garnered so much attention from the high school department, who weren't even directly involved.

​Thinking about it that way, Aouji's warning felt a lot heavier now. I had plenty of skeletons in my closet; if I didn't start behaving myself, I was going to end up fired.

"Troubles involving young male teachers are practically a tradition at all-girls schools, so I really think you should settle down as soon as possible, Aiba-sensei. By the way, do you really not have a significant other?"

"None, I'm afraid..."

"Oh? Then who is making those bentos for you every day?"

​An incredibly sharp counter from Yamashiro-sensei. There was absolutely no way in hell I could tell her that Aouji and Niira were the ones making them for me. I immediately activated my ‘Accelerated Thought’ skill.

"Uh, well... telling you there was someone making them was just me trying to show off in front of you, Yamashiro-sensei..." I mumbled, dropping my gaze.

​The two of them burst into giggles at my sheepish confession.

"Ufufu, I suppose I should be flattered that you felt the need to impress me."

"You really are young, Aiba-sensei. Well, I can't say I don't understand the feeling."

"But doesn't that mean you're actually quite a skilled cook? In that case, perhaps you could teach Kiyone sometime? Lately, she's been throwing tantrums and refusing to listen to a word I say."

​Yamashiro-sensei pressed a finger to her lip, casually tossing out the invitation.

​Instantly, Kumagami-sensei leaned in, his face dead serious for some reason.

"Aiba-sensei, you realize what just happened, right?"

"Huh? What do you mean?"

"An approach from a woman like that only happens when you're young. If you're interested, you absolutely cannot let this slip away. Take it from an experienced veteran."

"I honestly have no idea what you're implying..."

"Kiyone-chan is a sweet girl, and Yamashiro-sensei is a wonderful woman. Even if there is a bit of an age gap..."

​Oh, behind him, Yamashiro-sensei was activating her [Intimidation] skill again...

​Unable to bear watching the impending tragedy unfold, I made a swift retreat to the principal's office to deliver my report.

​

​Upon entering the principal's office, I was ushered to the guest sofa as usual.

​Principal Akechi, a stunning woman with medium-length hair who looked like a silver-screen actress, sat across from me. "Let us hear your report, then," she said, opening a small notebook.

"Right, well... three days ago, I was contacted by Niira-san and subsequently teleported onto her spaceship. She explained that an emergency had occurred on a planet within the Galactic Federation's jurisdiction, and she requested my assistance. I agreed, contacted Kumagami-sensei to handle my classes, and headed to that planet on Niira-san's ship. After completing the requested task, I returned to Earth yesterday."

​It was an incredibly rough summary, the kind of story that even a child could write a more believable lie for. Yet, the principal listened with absolute gravity.

"Was this emergency related to Niira-san's duties?"

"I can't share the details, but yes, it was."

"What exactly did you do there, Sensei?"

"Search and rescue. Helping free people who had been captured by bad guys... that sort of thing."

"Does that mean you engaged in combat with these 'bad guys'?"

"Yes. Usually, when people need my specific set of skills, it almost always involves some level of violence."

"Was this action legally sanctioned by the Galactic Federation's government?"

"Since it was a direct request from Niira-san and the government agency she works for, I believe so."

​Well, that was a bit of a grey-area answer. Judging by my conversation with Director Leidoban of the Galactic Federation Investigative Bureau, the legality of the whole thing was razor-thin. Still, that wasn't really my concern.

​The principal rested her chin on her hand, lost in thought for a moment, before nodding as if reaching a decision. She fixed her gaze on me.

"I see. Thank you for your report. Now, Aiba-sensei, I believe it is time I shared a little about the history of this academy, and about myself. Do you have some time?"

"Yes, as long as it fits within this period."

"Then let us begin."

​I hadn't expected to learn about the dark secrets of the academy today, but I suppose I'd finally earned enough of her trust. I sat back to listen.

"First, regarding Meiran Academy. It was originally founded by my great-grandfather with the goal of providing progressive education for young women. While it was quite unusual for its time, it was, at its core, an ordinary school."

"I see."

"However, my great-grandfather, who had connections across various industries, eventually realized something. In Japan—or rather, in this world—there are individuals who never appear in the public eye, yet are absolutely indispensable to the world's survival. Specifically, families like the Aoujis, the Kukamis, and people like Niira-san."

"Ah, that makes sense."

"For reasons of his own, my great-grandfather decided that he would support these individuals. Consulting with key figures from various fields, he established a system where the Akechi family would act on behalf of state institutions to support those operating in the shadows. In return, the government granted the Akechi family special privileges. That is how we carved out our unique position."

"He must have had an incredible sense of duty," I noted, intending to offer a compliment.

​But Principal Akechi merely let out a soft, slightly self-deprecating chuckle.

"I cannot say for certain. He may have simply been an eccentric, or perhaps he had something to gain. Whatever his reasons, this school took on the additional role of serving as a haven for those who walk in the shadows."

"And that legacy has been passed down to the present day."

"Precisely. I was raised to inherit my great-grandfather's legacy, and I accepted my position willingly."

"For a guy like me to end up here... even if it's just a coincidence, it feels a bit too perfect. It's almost bizarre," I said, scratching the back of my head.

​Principal Akechi narrowed her eyes, a soft warmth in her gaze.

"I completely agree. Moreover, the situations surrounding Aouji-san and the others have been unusually turbulent lately. From what I have gathered from the Aouji and Kukami families, if you had not come to this school, Aiba-sensei, some of these incidents could no longer have been kept hidden from the public. It really is a wondrous twist of fate."

"I've been feeling that way myself," I admitted.

​When I stopped to think about it, if I hadn't been here, the extermination of the Abyss beasts wouldn't have been completed in time, Crimson Twilight would have wreaked far more havoc, and we might have ended up in an outright war with an alien army. I seriously doubted whether simple "fate" was enough to explain all this... Personally, I felt "the Hero's curse of attracting trouble" was a much more accurate description.

"Given what you have told me, it seems highly likely that similar incidents will continue to occur. I know it places a heavy burden on you, Aiba-sensei, but I hope you will continue to lend them your strength. Of course, I will ensure you are compensated to the absolute best of our ability... May I count on you?"

"Of course. However, my only criterion for stepping in is whether their lives are in immediate danger. I may have played the Hero in the past, but I have no desire to serve as a tool of the state or play savior to the entire world anymore. I hope you can understand that."

"Understood. You have your own convictions forged from your past experiences, Aiba-sensei. I shall, of course, respect them completely."

"Thank you."

"That is all. Thank you for your report. You may return to your duties."

"Right, excuse me."

​I bowed and stood up. The principal rose with her usual fluid grace, then spoke as if suddenly remembering something.

"Ah, yes. I would love to hear about your time in that other world someday, Aiba-sensei. Have you shared your stories with anyone else?"

"No, not in any detail. Frankly, I'm still not entirely sure anyone actually believes me anyway."

​When I made a wry face, the actress-like beauty narrowed her eyes and gave a delightful giggle.

"In case you had any doubts, that simply means I must hear it even more. Fufu, it seems I truly do carry my great-grandfather's blood after all. Now that I can believe another world exists, my curiosity has gotten the better of me. How fascinating."

​

​After school, I held my first practice in three days for the General Martial Arts Club.

​Miruma came over to me and took the time to tell me, "I'm so glad you're back, Sensei." Meanwhile, the Amano-san girl was whispering to Niira, "Ririo-chan, no backdoor stealing him, okay?" But despite the usual noise, we proceeded with our magic power training as always.

​I started by having Miruma, Ayato, and Soutou practice projecting their magic power. Ayato had already mastered it at a practical level, but still had plenty of hurdles to clear, like mana compression. Miruma possessed a massive pool of magic power, so her training focused on controlling the output volume. Soutou was still green across the board, so her routine consisted of repeatedly venting her mana and drawing it back in.

​Meanwhile, Aouji, Amano-san, and Niira had advanced to hardening their magic power. Since all three of them fought with blades, their training involved enveloping their swords in a layer of condensed mana. Honestly, all three had already reached a functional level with this technique, so it was now just a matter of grinding their proficiency so they could use it in actual combat.

​Aouji seemed to have a good feel for it. Readying her mana-infused wooden training sword, she looked over at me.

"Sensei, is it safe to use this technique against the Abyss beasts now?"

"Yeah, I think you're ready," I replied. "Just test it out on weaker targets first. Things don't always go exactly as practiced in a real fight."

"Understood. I'll try it on a C-Class or lower first," Aouji nodded. "Master can use it too, right?"

"I should be able to," Amano-san chimed in, resting her wooden sword against her shoulder. "I'm excited to see how much power it packs. By the way, Aiba-sensei, do you keep this technique active at all times?"

​She stopped swinging her sword and bounced over to my side. She felt a little too close for comfort, but I was probably just imagining things.

"Yeah. The monsters in the other world couldn't be cut without magic power, so using it became second nature to me. Ah... I see. So that's why I've been able to cut them..."

​It was only then that a realization struck me.

​Honestly, I had always wondered why I was able to slice through the Abyss beasts with standard steel swords. After all, even top-tier swordsmen like Aouji couldn't cut them without a mana-infused blade.

​But when I thought about it, using magic power was as natural as breathing for me. Slicing through Abyss beasts like butter was actually the obvious outcome of my passive reinforcement. I was hit by a sudden, belated wave of surprise at how deeply ingrained my supernatural powers had become in my daily life.

"Aiba-sensei? Is something wrong?" Amano-san asked, tilting her head.

"Ah, no, it's nothing. At any rate, mastering this technique will give you a massive upper hand against the Abyss beasts. I'm looking forward to seeing your progress."

"Yes! I'll use this technique you taught us to slash through them left and right. Just watch me!"

​She leaned in even closer as she spoke.

​Yeah, she was definitely too close. Ever since the kidnapping incident, her attitude toward me had been transitionally different. Aouji had told me she "talked things out with her," but...

​I stole a glance at Aouji, who was currently glaring holes into me. Her gaze was fierce enough to suggest she might pounce and tackle me if I slipped up even slightly. Especially after the business with Rirara—the other day, I couldn't afford to let Aouji's opinion of me sink any lower. Frankly, she was terrifying when she was angry.

"Uh, right. Best of luck. You too, Aouji-san," I stammered, taking a step back.

​I quickly turned my attention back to Miruma and the others. Amano-san tried to float along after me, but Aouji grabbed her training collar from behind and dragged her back to their practice spot. It looked like I'd have to rely on Aouji to keep her on a short leash for the foreseeable future.

​Just then, a faint, prickling sensation ran down the nape of my neck. This feeling... it was a premonition of an Abyss Cave appearing. I pulled out the Dragon's Eye, a crystal-ball-like magic tool, from my ‘Spatial Magic’ storage. It had been a while since I last used it.

"Sensei! What's that?!"

​The ever-observant Soutou zipped over, staring at the Dragon's Eye with the wide, glittering eyes of a small animal spotting a treat.

"This is called the Dragon's Eye. It's a magical artifact that detects magic power over a wide distance," I explained.

"A magical artifact? Like the Gae Bolg?"

"It's the Magic Gun Tanegashima," I corrected her, ignoring her attempt to rename my weapon. "Now, let's see..."

​I activated the Dragon's Eye. Seven tiny points of light flickered inside the crystal orb; the one at the very center was me, and the other six represented the magic signatures of the girls in the room.

​I expanded the detection radius. One kilometer, ten kilometers, twenty kilometers...

"Hmm... This might turn into a bit of a headache," I murmured.

"Did something happen?"

​Soutou pressed up against my arm to peek into the crystal.

​The other girls stopped their training and gathered around. Amano-san tried to push past to squeeze in next to me, but Miruma was already standing in her way, effectively blocking her. Had she done that on purpose? Well, no time to worry about that now.

"It looks like three Abyss Cavees have opened simultaneously," I announced. "And judging by the signatures, they're expanding rapidly. This might get a bit tricky."

​My casual grumble instantly sent a wave of tension through the five girls who fought in the shadows. Sensing the gravity of the atmosphere, even Miruma—our resident "Saint"—grasped my hand, her face clouded with worry.

​

"Just as I thought. This one's the largest."

​I stepped back into the abandoned factory I had previously visited with Aouji.

​It seemed Abyss Caves generally manifested in deserted areas, which limited their spawning points. Though, I still couldn't be sure if these current ones were natural occurrences.

​In any case, the abandoned factory had once again been fully dungeonized, and the magic power leaking from deep within was incredibly dense. There was undoubtedly a A-Class or higher boss waiting at the end.

​This was an unprecedented situation even for the Aouji family. Given the urgency, it was decided on the spot that our makeshift group would handle it. However, the only ones capable of actually entering the Abyss Caves were me, and the specialists: Aouji and Amano-san. Even though Soutou, Ayato, and Niira were highly capable fighters, I hesitated to drag them into an actual Abyss Cave. Frankly, it wasn't their responsibility in the first place.

​So we divided our forces. I would clear the first trench solo, while Aouji and Amano-san teamed up to tackle the second. For the third, Soutou, Ayato, and Niira would camp near the entrance to keep watch. Of course, they would have to dispatch any Abyss beasts that managed to spill out, but I lent them the Magic Gun Tanegashima and some other gear, so they had more than enough firepower.

​The only real hiccup was that Miruma insisted on coming along too. Even Ayato chimed in, saying, "Why not let her join us?" so I gave Miruma a Ring of Protection and had her accompany Soutou's group. She was a powerful healer, making her a viable party member, but... I'd definitely have to report this to the principal and her parents later.

​With the plan set, I began a speedrun of the Abyss Cave before me.

​The Abyss Cave itself was much like the last one, with the factory's interior warped into a dungeon. Slicing through the spawning C-Class beasts as I sprinted past and instantly vaporizing the Class B and A-Class mid-bosses in their respective rooms, I reached the boss chamber in about thirty minutes. Since I barely paused to collect any Abyss Drops, it was a breeze.

​The creature waiting in the boss room was none other than a Special Type I—a humanoid, horned, winged, and tailed demon-like Abyss beast similar to the Greater Demon I had fought before. This definitely wasn't something Aouji and the others were ready to handle.

​But to me, it was just another mob. I bisected it in a single swing with an invisible slash from my Demon Sword Diabla, clearing the dungeon. After gathering the Abyss Drops, the trench dissolved into nothingness. It seemed this one had indeed been natural.

​I rushed outside, activated my ‘Flight’ magic, and took off into the darkening sky, heading straight toward Soutou and the others.

​

​By the time I arrived over the abandoned timber yard nestled against the mountainside, Soutou and the others were already engaged in combat.

​A pack of five six-legged, tiger-like Abyss beasts was huddled together, surrounded by Ayato wielding the Holy Sword Durandal, and Soutou and Niira leveling the Magic Gun Tanegashima and other weapons.

​Miruma stood a short distance away, keeping a brave, steady watch on the battle.

​As soon as I touched down nearby, Miruma noticed and came jogging over.

"Welcome back, Sensei," she said.

"Sorry I'm late. How are things looking?" I asked.

"We're doing well. This is the fourth wave of those Abyss beasts. Everyone is so strong that I haven't had to use my healing powers once, but... I had no idea such terrifying things were happening in places I never knew about. It's quite shocking."

"Yeah, I get it. I was pretty surprised myself at first."

"Even you, Sensei? Though for me, you are the biggest surprise of all. I never imagined you could fly or use magic," she said, her voice filled with a quiet intensity.

​She seemed unusually focused on me.

​Well, I wasn't entirely sure what was going on in her head, but she seemed surprisingly unfazed. Seeing how she wasn't particularly terrified of the Abyss beasts, she might actually have a lot more steel in her spine than her gentle appearance suggested.

​While we were talking, the other three finished off the Abyss beasts and gathered around us.

"Sensei! You cleared your trench! So, are we heading into this one next?" Soutou asked, her eyes glittering with curiosity as she stared at the gap between the trees.

​She looked at the Abyss Cave that had torn open the forest.

"Yeah. I'll clean this up real quick, so sorry, but just hang tight out here for a bit."

"Aiba-sensei, please let me go in with you! An opportunity to do something this fun doesn't come around very often," Ayato insisted, stepping forward as I turned toward the entrance.

​The other three fell into step right behind her, clearly preparing to follow us in.

"I mean, I get the enthusiasm, but..."

"Didn't you promise the other day that you'd let us join if a good opportunity came up?" Ayato countered with a smirk.

​Come to think of it, I did say something like that. There really weren't many chances for someone of Ayato's caliber to let loose, and she wasn't about to let this one slip away.

"Alright, fine. Uh... do the rest of you want to experience an Abyss Cave too?" I asked, looking at the group.

​Soutou, Niira, and even Miruma nodded vigorously in response.

"...Well, let's go then. Just don't expect it to be a walk in an amusement park."

​Since they were helping me out of the goodness of their hearts, letting them tag along wouldn't hurt. Given the recent string of anomalies, I might need to ask for their cooperation again down the line anyway.

​The Abyss Cave turned out to be a dungeon modeled after a forest. Dense trees towered over us, with an incredibly unnatural path winding deep into the interior.

"Whoa, so this is an Abyss Cave~ Misono told me about them, but seeing it is totally surreal," Soutou marvelled, looking around.

"It is my first time entering one, but a phenomenon that manifests such a localized dimension is completely unheard of," Niira remarked clinically.

Ayato's eyes were practically sparkling like a kid at a theme park. "So if we keep going, those 'Abyss beasts' will keep popping up, right? I can't wait!"

​Well, she could easily solo a A-Class, so I figured I'd let her have her fun for a bit.

"Remember, this is technically an emergency, so no playing around," I warned. "I'll take the lead. Niira-san, watch our six. If any Abyss beasts show up, Ayato-san, they're all yours."

​Just as I finished giving orders, four six-legged C-Class tigers lunged from the shadows. Ayato sliced through them in rapid succession with the longsword Durandal I'd lent her. I already knew she was capable, but her reaction speed and physical capabilities were downright terrifying. The way she occasionally moved so fast it looked like a skipped frame in a video was incredibly close to my own ‘High-Speed Movement’ skill. While her pure swordsmanship was inferior to Aouji's, her raw strength and explosive power more than made up for it. If her stamina held out, she could probably clear a standard Abyss Cave entirely on her own.

​Every now and then, the forest opened up into small clearings where B-Class four-armed giant mantises and four-trunked elephants appeared. But Ayato simply laughed, shouting, "Haha! Now we're talking!" as she hacked them to pieces.

​With nothing to do, Soutou poked me from behind as we walked.

"Sensei, do treasure chests not drop in these Abyss Caves?"

"I've never seen one. Aouji-san didn't mention anything either, so probably not," I replied.

"Ehh? That's so boring."

"Well, the Drops are the real treasure here. Oh, looks like the end is just ahead."

​Up ahead stood a massive, towering tree, its branches spreading wide enough to blot out the sky. The clearing in front of it radiated a heavy, unmistakable boss-room energy.

"Judging by the pressure, a A-Class is about to show up. Let me know if it's too much to handle," I said, stepping into the clearing.

Ayato waved her hand dismissively and stepped past me. "No way I'm letting you steal the spotlight. Slaying a strong opponent is the whole point!"

​As she spoke, a dark, thick mist swirled at the base of the giant tree, and a A-Class Abyss beast resembling a long-armed gorilla materialized.

"Looks like it's got some spine! This is going to be fun!" Ayato grinned.

​She lunged at the chest-beating Class A gorilla. Dodging its spat fireballs with inhuman reflexes, she slipped inside its guard and swung her blade.

​The gorilla shrieked as its chest was slashed open, swinging its long arms to crush Ayato's slender frame. But Ayato backstepped fluidly, severing its elbow in a swift counter-slash.

​However, she couldn't completely avoid the follow-up blow from its other arm. It wasn't a clean hit, but the massive fist clipped her shoulder, sending her flying.

"Daimon-san!" Miruma screamed.

​But I knew a blow of that caliber wouldn't put her down.

Ayato sprang back to her feet instantly. Charging once more through the fireballs, she ducked beneath its flailing arms and hacked off its leg. As the beast collapsed, she sheared its head clean off, completing a solo extermination of a Class A Abyss beast.

"Ow, ow... Yeah, I can't take these things lightly," Ayato muttered, walking back to us while rubbing her shoulder. "They're way tougher than those Crimson Twilight synthetic soldiers."

​Miruma rushed to her side. "Are you alright?" she asked, channeling her Healing Power.

​Come to think of it, this was the first time I'd seen her use her abilities. It was as if she were executing ‘Recovery Magic’ directly as a skill without drawing any magic circles, and the potency was remarkably high. If it was equivalent to high-tier ‘Recovery Magic’, it made sense why it left her so physically drained.

​While we watched, the forest dissolved, reverting back to the abandoned timber yard. This trench had also been a natural anomaly.

"Whoa~ So it just vanishes once the boss is dead. Truly a bizarre space," Soutou said.

"It bears similarities to a Lambda Space Blockade. The fact that such a thing occurs naturally is astonishing," Niira observed.

​As Soutou and Niira shared their thoughts, my phone buzzed. It was Aouji.

​'Sensei, we've successfully cleared our Abyss Cave. Both of us are unharmed.'

"Good work. We've finished clearing our two as well. No issues on our end."

​'You were a huge help. What should we do now?'

"It's getting late, so let's call it a day and head home. We'll talk more tomorrow."

​'Understood. We can walk to the station and take the train back from here, so we'll be fine.'

"Got it. I'll get everyone here home safely, so you two go straight back and get some rest."

​I hung up and looked at the group.

​The Abyss Cavees had absolutely nothing to do with these four girls, but they'd ended up dragged into the thick of it anyway. Still, fostering cooperation among these girls with complicated backgrounds might be necessary in the future. After all, the factions they were fighting seemed to be connected behind the scenes anyway.

​

​After using Niira's Lambda Transfer to send everyone home, I was flying through the night sky toward my apartment.

"Yeah... there has to be a reason for this," I muttered to myself.

​The sudden spike in Abyss Cave anomalies was undeniable. According to Aouji, their manifestation was supposed to be extremely rare, and a Class A appearing was a once-in-a-century event.

​But now we had three opening simultaneously, and even a Special Type I—which was above Class A—spawning naturally. This was definitely not normal. It was only logical to assume there was an underlying cause.

"If this were the other world, I'd assume it was the Demon King's resurrection... but there shouldn't be a Demon King here..."

​As I grumbled, another sharp prickle stung the back of my neck.

​I pulled out the Dragon's Eye to check. A few moving points indicated Aouji and the others. But besides them... there was a massive reaction right around the Kukami estate. Wait, is this a bad one?

​I funneled mana into my ‘Flight’ magic and accelerated toward the Kukami mansion.

​

​The reaction was indeed coming from inside the Kukami mansion.

​However, looking down from above, there were no visible signs of damage to the estate. That meant whatever was happening was indoors... most likely, an Abyss Cave had opened inside.

​But if that had happened, they should have contacted me or Aouji. The fact that they hadn't meant they were facing an extreme emergency.

​I touched down and scanned the mana signatures. I had assumed it was inside the mansion itself, but the reaction was actually coming from deep underground. Searching the perimeter, I found a ramp designed for vehicles leading down into the subterranean levels. Apparently, they had an underground parking garage. As expected of the ultra-wealthy Kukamis, their home layout was on an entirely different scale from ordinary citizens.

​Since there was no one around to stop me, I slipped down the ramp. Following the curved path toward the garage, I gasped as I saw that the tunnel itself had been swallowed by the entrance of an Abyss Cave.

"I really hope they didn't drive right into this..." I muttered.

​While you wouldn't normally speed down a garage ramp, the entrance was positioned in a way that even if you slammed on the brakes, you'd likely slide right in. Of course, they could have just backed out once they realized, but...

"Well, only one way to find out."

​With my mithril sword in hand, I stepped into the Abyss Cave.

​

​The interior of the Abyss Cave looked like a continuation of the concrete underground tunnel, wide enough for cars to drive through. Looking back, I realized the entrance had been replaced by a solid concrete wall. It was one of those dungeons where you couldn't escape until the boss was defeated.

"Yeah, this definitely feels like a trap."

​If no one else had entered before me, it would be fine. But my Hero's intuition was screaming that Kukami and her entourage had already gone deep inside.

​I immediately burst into a sprint. If it was just trash mobs, her maid Usa-san and her butler Nakadachi-san should be able to handle them. But mid-bosses and the final boss were a different story. Given the ambient pressure of this Abyss Cave, there was bound to be a Class A waiting at the end.

​I sliced through the C-Class beasts that crossed my path. I passed three large clearings along the way, which had clearly been mid-boss rooms. The fact that they were empty meant they had already been cleared.

​Deeper inside, I spotted what looked like the final chamber. In the center of the wide open space sat a portion of the black luxury sedan Kukami usually rode in. Or rather, only a portion of it remained. The rest of the vehicle had been cleanly bitten off, vanishing entirely.

​The boss room resembled a massive underground parking garage, large enough to hold about a hundred cars. In the dead center stood three figures huddled together.

​Circling them was a colossal, fifty-meter-long giant earthworm. It was a Class A Abyss beast I had encountered once before. Its mouth split open in a grotesque cross-shape, snapping as it eyed its prey, waiting for the perfect moment to strike.

​The three targets were in a dire state. The blonde, drill-haired Kukami Sekai stood frozen, completely helpless, while Nakadachi-san frantically held up a protective barrier beside her. At her feet, Usa-san, the glasses-wearing maid, was on one knee, her breathing ragged. She clutched her one-handed mace, Ah-Un, in her right hand... but her left arm had been cleanly severed from the elbow down. This was bad.

​I closed the distance in a fraction of a second using ‘High-Speed Movement’, mincing the giant worm into pieces with my mithril sword.

​As the worm dissolved, Nakadachi-san collapsed to his knees, dropping the barrier upon seeing my face. He was completely exhausted, but otherwise uninjured.

"Sensei! Usa is...!" Sekai cried out, rushing to Usa-san's side. The proud ojou-sama was completely beside herself with panic.

"It's okay, leave it to me," I assured her.

​I knelt beside Usa-san and cast ‘Recovery Magic’ on her. While it would stabilize her and dull the pain, standard magic couldn't regenerate a lost limb.

​Having survived the immediate crisis, the tension keeping Usa-san conscious snapped. She mumbled, "Milady..." before starting to limp forward. I caught her slender frame, pulling a vial of medicine from my ‘Spatial Magic’ storage. It was an Extra Potion—a miraculous elixir capable of regenerating lost limbs, something that would be considered a divine miracle in this world.

"Drink this before you lose consciousness," I said, uncorking the bottle and pressing it to her lips. Under any other circumstances, this would be an incredibly heart-pounding situation.

"Mmh..."

​The potion was notoriously foul-tasting, but Usa-san swallowed it in one gulp. She immediately drifted into a deep sleep, and I gently laid her down on the floor.

"Sensei, thank you so much for saving us. Will Usa be alright...?" Kukumi asked, her eyes glued to her maid's face. The usual haughty ojou-sama facade was replaced by deep anxiety. This had been a truly close call.

"She'll be fine. Her arm is already growing back, see?" I replied as I cast ‘Recovery Magic’ on Nakadachi-san as well.

"Yes... wait, what?!"

Kukumi gasped, her eyes widening as she stared at Usa-san's fully regenerated left arm.

"Wh-What?! It's... it's really back...!"

​Well, anyone would be shocked seeing that for the first time.

Kukumi gently touched the arm to confirm it was real, then looked up at me in disbelief.

"I can scarcely believe it, but it's completely healed. Sensei, what in the world did you just do?"

"It's a highly potent medicine called an Extra Potion. It can regenerate severed limbs. Though, I don't have very many of them left," I lied. In reality, I had a practically endless supply of them, but telling her that would likely lead to a headache.

"A medicine capable of regenerating lost limbs... Something like that must be priceless!"

"I just use it when it's needed. More importantly, this Abyss Cave isn't dissolving. That means it's an artificially placed type."

​Scanning the surroundings, I spotted a pitch-black, glowing orb embedded in the concrete wall.

​I walked over and pried the Abyss Core out of the wall. Instantly, the distorted space dissolved, reverting back to a standard underground parking garage large enough for about ten cars. I could see the white sports car belonging to Kukumi's father parked nearby. We were definitely back.

"We are... back, then," Nakadachi-san sighed, standing up. The usually unflappable butler looked thoroughly exhausted.

"Aiba-sama, you have my deepest gratitude once again. Usa and I were truly at our limits this time."

"I'm just glad I made it in time. You did incredibly well holding out against a Class A."

"We never anticipated a Class A would manifest here. We acted too hastily. We should have waited for you, Aiba-sama."

"Yes. If anything happens, I'll likely sense the mana fluctuations, so waiting for me in the future would be much safer. Still, this trap was incredibly blatant."

​I added that last part because I had a very good idea of who was behind this Abyss Cave trap. The culprit was likely Gonnouchi, though the Kukamis were still in the middle of gathering solid evidence against him.

​But trying to assassinate Kukami Sekai inside her own home was crossing a line. The Kukami family had to be reaching their breaking point.

​But Nakadachi-san simply lowered his eyes and shook his head.

"Indeed. However, the master has instructed us to bide our time... so our hands are tied."

"So you still haven't caught Gonnouchi-san red-handed," I summarized.

"Yes, that seems to be the case. At any rate, we have been ordered to focus entirely on protecting the young lady and avoid making any preemptive moves."

"I see. So because Kukumi-san has stopped going out as much, they decided to bring the fight straight to her?"

​When I tossed out that theory, Kukumi looked up, a dark shadow passing over her eyes.

"Perhaps Gonnouchi is simply reaching his limit as well," she whispered. "Unable to contain the hatred festering within him."

"Hatred?"

"Yes. Gonnouchi lost his only daughter in an accident years ago. Gonnouchi Midori-oneesama... she was like an older sister to me..."

"That is tragic. But how does an accident lead to a grudge against the Kukamis?" I asked, furrowing my brow.

"As the heir to the Kukami family, I was training to channel power from the Abyss Drops. But during one of my practice sessions, I made a mistake and accidentally summoned a Abyss beast. And... Midori-oneesama threw herself in front of me to protect me..."

"...Ah. I see."

​Well, that was incredibly heavy.

​A loyal servant's daughter sacrificing her life to save the young mistress of the house. And when the cause of the accident was the mistress's own blunder... it was only natural for bitter resentment to fester.

​If Gonnouchi was obsessed with using Abyss beasts to assassinate Kukumi because of how his daughter had died, his hatred must run incredibly deep.

​Honestly, as a former Hero, this was exactly the kind of interpersonal melodrama I preferred to steer clear of... But I had made a promise to Kukumi's father, Jinma-san, so turning a blind eye wasn't an option.

​— Executive Office, Kukami Conglomerate —

"I see. It was truly a close call, then. I am glad you are safe. We must express our deepest gratitude to Aiba-sensei once more."

​'Yes, indeed. Also, Misono informed me that aside from the one at our mansion, three other natural Abyss Cavees manifested simultaneously.'

"Three Abyss Caves? Is this the spatial distortion caused by the overuse of Abyss Cores finally manifesting?"

​'Quite possibly. In any case, their movements are becoming far too reckless. I suspect Gonnouchi is losing his composure.'

"No doubt. But thanks to their desperation, we have finally caught their tail. We will catch him in the act next time. The danger to you will be over soon."

​'Regarding that... couldn't we simply ask for Aiba-sensei's assistance from the start?'

"No, that would only sour Aiba-sensei's opinion of us. Powerful individuals often withdraw the moment they feel they are being used. To ask a favor of someone of his stature requires appropriate resolve on our part as well."

​'I see... He certainly does carry himself with that kind of quiet authority.'

"For this operation, we will mobilize everyone from the Usa family. I have also requested assistance from Kochihara. We will have more than enough combat capability."

​'Yes, I agree. Though, I am simply relieved that Usa did not have to lose her arm permanently.'

"Lose her arm? What do you mean?"

​'In truth, Usa lost her arm during the battle with the Abyss beast. But Aiba-sensei used a special medicine to completely regenerate it on the spot.'

"Hmm... If such a medicine actually exists and were to enter the market, it would easily fetch hundreds of millions of yen. For Aiba-sensei to possess such... No, he was a Hero, after all."

​'Indeed. And... I felt it acutely today. Does Gonnouchi truly harbor such deep resentment over what happened to Midori-oneesama?'

"Midori-chan... But as I have told you countlessly, that accident was not your fault. We simply never found the true culprit. Even if Gonnouchi directs his resentment toward you, you must not let it weigh on your conscience."

​'Yes...'

"I explained this to Gonnouchi as well, but coming from me, it likely sounded like nothing more than an excuse. In any case, everything will be settled soon. Including how we will handle Touma..."

―― Servants' Quarters, Kukami Estate

"Mnh... Where... Milady...?"

"Usa! Thank goodness... This is your room. Once again, you have protected me beautifully, haven't you?"

"To protect you, Milady... No, to show such a pathetic state this time, I am utterly ashamed. Even with Aiba-sama lending us his strength, to not even be able to defeat a single worm..."

"But Usa, weren't you fighting all by yourself until he arrived? That was entirely a failure of my tactical judgment. If only I had remained calm, I wouldn't have forced you to overexert yourself."

"That is not true, Milady. Even if we had stayed in that Abyss Cave, we would have only been overwhelmed by the endless waves of Abyss beasts. Your decision was not incorrect."

"Thank you, Usa. I am truly glad you are safe."

"To hear you say such words brings me the greatest joy. By the way... did Aiba-sama ultimately save us? Faintly, I feel as though I was supported in Aiba-sama's arms..."

"Yes. Speaking of which, do you remember having your arm severed, Usa?"

"Yes, I remember it vividly. My left arm... My left... Huh? Why is my left arm still here? Was it all a dream...?"

"No, Aiba-sensei healed that as well. He called it an 'Extra Potion.' It seems he possessed a miraculous medicine."

"A medicine capable of restoring a lost limb... Just how far does Aiba-sama's power reach...?"

"Furthermore, one of your weapons was eaten, wasn't it? He left a replacement in its stead."

"This... I can feel a tremendous power radiating from it. To casually hand over something like this... what could Aiba-sama possibly be thinking?"

"He said, 'People who work hard deserve an appropriate reward, don't they?' I believe he has a rather unique set of values forged from his own experiences."

"He is a mysterious gentleman indeed. Yet, I have incurred a debt to Aiba-sama that I can never fully repay. I cannot simply do nothing, but..."

"I feel the same way, Usa. My father will likely offer some form of compensation, but frankly, I believe this exceeds what can be settled with money alone. Once our current predicament is resolved, let us properly consult Sensei. Until then, you should accept his goodwill with grace."

"Understood, Milady. I shall do so."

"Since you are so beautiful, Usa, perhaps he might even propose to you. Fufu, I suppose you would be free to turn him down if he does."

"M-Milady?! I doubt such a thing would ever happen... but if he did request it, I would indeed be troubled. My duty is to protect you, after all."

"Oh? So you wouldn't be troubled by the proposal itself, then?"

"N-No, that is not what I meant at all..."

"Ufufu, I am merely teasing. Though, I wouldn't mind if you protected me as husband and wife."

"Milady...! Honestly, please stop teasing me. But if he really... no, it is nothing!"