3rd Person POV
The clubhouse was still wrapped in the hush of early morning when Rias stirred awake. Sunlight slipped through the gap in the curtains, painting thin golden lines across the bed. She blinked, rubbed her eyes, and immediately noticed two things: First, Akeno was still deeply asleep beside her, breathing slow and even, one arm thrown carelessly over the pillow. Second,Their wrists were still loosely bound by the rope from last night.
Rias exhaled quietly through her nose, reached over with her free hand, and began carefully untying the knot. The rope came away without much fuss. She rubbed her wrist once, slid out of bed as silently as possible, picked up her clothes from the floor and tiptoed toward the door.
A sleepy, sultry voice stopped her mid-step. "Look who decided to forfeit the game~"
Akeno had rolled onto her side, violet eyes half-lidded, lips curved in a lazy, victorious smile. She stretched languidly, making no move to cover herself. "Which means I win. Now…"
She swung her legs out of bed and stood—completely naked—heading straight for the door with clear intent. Before her fingers could touch the handle, Rias lunged. In one fluid motion she tackled Akeno back onto the mattress, pinning her shoulders down. The two devils wrestled briefly—more playful than serious, but with enough strength to make the bedframe creak. "No sneaking, Akeno," Rias huffed, keeping her Queen's arms pressed to the sheets. "You're making him uncomfortable."
Akeno laughed breathlessly, squirming just enough to be a nuisance. "But he needs his beloved Akeno~ Besides, I'm not sneaking… I'm rushing."
The struggle lasted maybe three minutes—pillows were knocked to the floor, hair became mussed, and at one point Akeno nearly flipped Rias over. In the end, Rias managed to get her into a hold she couldn't easily escape from. Akeno finally went limp with an exaggerated sigh. "Fine, fine… you win this round, President."
Rias waited another ten seconds to be sure, then released her. Akeno immediately curled up on her side like nothing happened, already half-asleep again. Rias shook her head, gathered her clothes and slipped out. She paused briefly outside Arto's door, tried the handle—locked, as promised—and smiled despite herself. Good.
After a quick shower and changing into her school uniform, she headed downstairs to the living room. A teleportation circle was already shimmering in the corner. Sona Sitri stepped through a moment later—black bob perfectly in place, pink oval glasses catching the morning light, expression as composed and mildly impatient as ever. "What do you need, Rias?" she asked without preamble. "It must be urgent if you're calling me this early."
Rias gestured to the sofa. "Yes, Sona. I need your help to clear a new transfer student before school starts again."
Sona raised an eyebrow and sat. "New peerage member?"
"Not exactly. He's been here two days. I want to keep him close to us."
Sona's gaze sharpened. "You didn't tell me about him. We rule this town together, Rias. Information should be open and honest between us."
"I know. I'm sorry—I completely forgot in the chaos. But he's not in my peerage."
"Then why keep him close? Don't tell me he's some dangerous entity you accidentally took in."
"No, nothing like that. He's… normal." Rias hesitated, then continued. "Do you remember the stray group that's been annoying us for weeks?"
Sona nodded. "They were a pain."
"We set up a trap—treasure chamber full of mimic chests. When we arrived, the strays were unconscious or dead… and six mimics were shredded. The one responsible was this man. He did it while extremely exhausted. We could hear him panting from across the room. Even in that state, he was faster than Kiba. It took us forty-five minutes of chasing to corner him."
Sona's brows climbed. "He killed six mimics while half-dead? That's… exceptional."
"Exactly. After we explained the situation, he collapsed. We brought him back here. He's been with us since."
Sona leaned back, studying Rias. "And you didn't recruit him?"
"I offered. He declined."
Sona's lips twitched. "Well then—"
Rias lifted the red Knight piece from her pocket and set it on the table between them. "I promised him I'd save him with this if he ever ends up on the verge of death. This piece is reserved for him. You don't get a shot at recruiting him."
Sona stared at the chess piece for a long moment, then sighed. "Fine. But I still want a chance to talk to him. Maybe your offer wasn't compelling enough."
Rias smirked. "I'd love to see you try."
"In return for giving me that chance, I'll handle his enrollment paperwork. What's his name?"
"Arto Abyssgard."
Sona paused. "…Abyssgard? That might draw attention. We should adjust it slightly—something less conspicuous."
"I'll ask him. Thank you, Sona."
"It's only fair." Sona stood, brushing invisible lint from her skirt. "Send me his measurements for the uniform. And which year?"
"Second year. Same as us."
"Got it." Sona opened a new teleportation circle. "Goodbye for now. I have matters to attend to."
"Have a great day, Sona."
The circle closed. Rias sank onto the couch, leaning her head back with a tired sigh.
A sultry voice floated down the stairs. "He's going to school with us? So I get to spend even more time with him…"
Akeno descended—hair still slightly sleep-tousled, wearing a loose robe that did little to hide her figure—carrying a cloth tape measure and practically humming.
Rias sat up. "Good morning, Akeno. You sound very happy today."
"Why yes, I am~" Akeno twirled the tape measure around her finger. "I get to take Arto's measurements. I've been dying to know his numbers. Arms… chest… abs… legs… and maybe…" She gave a dreamy little sigh and danced toward the stairs. "I'll start right now~"
Rias shot off the couch. "Hey! Cut that out!" She chased after her Queen. "I'm the one taking his measurements. Leaving you alone with him is dangerous!"
Akeno spun on the landing, holding the tape measure behind her back. "So you've decided to play the game properly, huh?" Her grin was pure mischief. "You'll have to defeat me to get this tape measure. Otherwise I'll enjoy the honor of measuring that strong body up close."
Rias's face went scarlet. "Akeno, give me that tape measure right now!"
"So you do like looking at his body too? How naughty of you, Rias~"
"I DON'T CARE—GIVE ME THE TAPE MEASURE!"
Upstairs, muffled arguing and laughter echoed down the hallway.
[Timeskip: Brought to you by chibi Akeno and chibi Rias playing rock paper scissors, and Akeno came out victorious]
The hallway outside Arto's room had become a battlefield of wills. After an intense, whispered rock-paper-scissors showdown (best of five, with dramatic pauses and accusations of cheating), Akeno emerged victorious—tape measure raised like a conquered flag. Rias trailed behind, clutching the enrollment forms with a defeated scowl, cheeks still pink from the earlier "negotiations."
Akeno knocked lightly on the door, voice dripping honey. "Arto, darling~ Can you let us in? We need to talk to you~"
The door opened almost immediately.
Both women stopped breathing for a solid three seconds. Arto stood there fresh from an obvious morning training session—completely shirtless, skin glistening with a light sheen of sweat that traced the lines of old scars and hard-earned muscle. His hair was tousled, a few strands clinging to his forehead. Loose training pants hung low on his hips, revealing the sharp V-cut that disappeared beneath the waistband.
His eyes blinked innocently at their stunned silence.
A synchronized thought echoed in both their minds:
Oh my… he's hot… I can never get tired of this.
Rias's face went crimson first. Akeno's followed a heartbeat later, violet eyes wide and appreciative.
Arto tilted his head, oblivious. "What is it, ladies?"
Rias recovered—barely—voice coming out a little higher than usual. "C-can we come in?"
He stepped aside without hesitation. "Of course."
They entered quickly, trying (and mostly failing) not to stare as he closed the door. Rias and Akeno sat on the edge of the neatly made bed; Arto remained standing, arms loosely crossed, completely comfortable.
Rias cleared her throat and held up the forms. "Here's the matter, Arto. Are you interested in school? You know—where people learn together in classrooms?"
Arto's expression brightened with genuine curiosity. "Yes. Very interested. I've never been to one."
Akeno, who had been about to start measuring, paused and pointed past him to the desk. "Okay… but how do you explain that?"
Floating above the open magic primer Rias had given him were several intricate, glowing circles—Arto's own hybrid constructs, slowly rotating as they interfaced with the demonic sigils on the page. Handwritten notes in his precise, archaic script covered scattered papers: equations, flow diagrams, translation keys.
Arto glanced over his shoulder and shrugged modestly. "Oh, come now. I've lived three thousand years. I had to learn somehow."
Rias leaned forward, fascinated. "Without any school? Or teachers?"
Arto rubbed the back of his neck, a touch sheepish. "Well… I suppose you could call it self-homeschooling."
Akeno tilted her head, tape measure dangling forgotten for the moment. "Elaborate?"
He sighed, leaning against the desk. "Fine. I studied everything on my own. As leader of the Abyssgard Legion, I needed to understand strategy, logistics, magic, politics—everything to run the army smoothly. But no one would teach me directly."
Rias frowned. "Why not?"
"They were… afraid of me." He looked genuinely puzzled. "I never understood it. Do I look scary to you?"
Both women shook their heads vigorously—perhaps a little too vigorously.
Arto blinked. "Huh. Then I never figured out why no one would meet my eyes. Or why they acted so strangely…"
Realization dawned slowly, expression turning wry. "Oh. Right. The puppet thing."
Rias and Akeno exchanged glances. "Puppet?" Rias prompted gently.
Arto's voice took on a dry edge. "Some faction leaders wanted a clueless figurehead they could control. Classic political maneuver. So I played dumb for about a century—let them think I was the perfect, obedient living weapon."
He gave a small, dark chuckle. "Took time, but eventually I ruled with my own insight. Anyone who tried to manipulate me after that… well. They learned not to provoke a two-thousand-year-old smart living weapon."
The room went quiet for a beat. Akeno let out a low, appreciative whistle. "That's… terrifyingly impressive." Rias just stared, a mix of awe, sympathy, and quiet anger on her face—at the people who had treated him that way for so long.
Arto shrugged again, as if it were ancient history. "Anyway—school sounds much more pleasant. When do we start?"
Rias recovered, holding up the forms with renewed energy. "Right now, actually. We just need your measurements for the uniform and a few details…"
Akeno twirled the tape measure with a triumphant, predatory grin. "And I believe I won the right to take those measurements~"
Arto glanced down at himself—sweat still cooling on his skin, hair sticking in damp strands—and gave an apologetic nod. "O~kay? But first, let me take a shower. I'm all stinky and sweaty now. It'll only take a few minutes."
Rias waved a hand quickly, cheeks still faintly pink. "It's okay, take your time, Arto…"
Akeno's eyes lit up with instant mischief. She leaned forward, lips already forming the dangerous words. "Now that you mention it, I haven't had a shower either. How abo—"
Rias's hand shot out like lightning, clamping firmly over Akeno's mouth. "Hmhmhmhm!" Akeno protested, violet eyes wide and sparkling with suppressed laughter.
Arto blinked, confused. "Yes, Akeno?"
Rias's smile was tight, strained, the picture of innocence stretched to breaking point. "It's nothing. Quick—go get your shower."
Arto looked between them—Rias's iron grip on Akeno's face, Akeno's muffled giggling—then decided (wisely) that some questions were better left unasked.
He offered a small, puzzled nod and headed for the en-suite bathroom attached to his room, closing the door behind him with a soft click. The moment the lock turned, Rias released Akeno and rounded on her. "Not. A. Word," she hissed, finger jabbing accusingly. "We are not turning his first school enrollment into one of your shower fantasies."
Akeno rubbed her jaw dramatically, pouting. "You're no fun, President~ He literally invited the idea."
"He did not invite anything. He's too pure for this world."
Akeno's pout melted into a fond smile. "That's exactly why it would have been fun."
Rias groaned, slumping back onto the bed. "Just… behave. For five minutes. Please."
From the bathroom came the sound of running water and the faint rustle of clothes hitting the floor.
Akeno flopped beside Rias, tape measure still clutched triumphantly. "Five minutes is plenty of time to plan," she murmured conspiratorially.
Rias buried her face in her hands.
"Arto, hurry up in there… before she corrupts us both."
[Timeskip: Brought to you chibi by chibi Akeno tries to sneak into the bathroom, but pulled away by chibi Rias]
The bathroom door opened with a soft click. Arto emerged, towel slung casually over one shoulder, wearing only loose training pants that hung low on his hips. His skin was still slightly damp, hair dark and tousled from the quick shower, carrying the faint, clean scent of soap.
Akeno's eyes lit up like a predator spotting prey. "Come here, darling~" she purred, patting the bed beside her. "Let me see how big you are~ Rias, prepare to write~"
She smirked, tape measure already unfurled. Rias stood nearby, clipboard in hand, pen poised—but a dark crimson aura flickered around her, eyes narrowed in barely contained irritation.
Arto noticed immediately. Instead of approaching Akeno, he walked straight to Rias and wrapped her in a gentle, steady hug—arms around her shoulders, careful not to overwhelm. The effect was instantaneous.
The menacing aura vanished as if it had never existed. Rias's tension melted; her eyes fluttered half-closed for a moment. Arto's voice was low, calm, meant only for her. "What's bothering you, Rias? You can whisper if you don't want anyone to hear."
Rias inhaled slowly—warm skin, fresh soap, something uniquely him—and felt the last of her jealousy evaporate. "Warm and fragrant… in your face, Akeno."
She gave a small, contented hum.
"I'm perfectly fine," she murmured. "You don't need to worry."
Arto pulled back just enough to check her face. Seeing the aura truly gone and her expression relaxed, he nodded, satisfied.
"Okay then. Where were we?"
Akeno watched the entire exchange with open fascination.
"He calmed her down instantly. Impressive." She patted the bed again. "Measuring time~"
Arto obligingly stepped closer. Akeno began wrapping the tape around his body with practiced efficiency—and occasional not-so-practiced lingering.
Rias cleared her throat, pen ready.
"Arto?"
"Yes?" He lifted his arms obediently as Akeno measured his chest—letting out a tiny, involuntary breath when she "accidentally" pressed a little too firmly.
"About your name," Rias continued, jotting down the numbers. "Abyssgard might cause… questions among students. I recommend changing it slightly for school."
Arto nodded thoughtfully.
"Right. How about Aruto Abyga? Sounds close enough, but less… dramatic."
Rias smiled. "Perfect." She wrote it down. "And birthday?"
Arto paused. "I… don't know." Rias blinked. "You don't?"
"I've never celebrated one. Choose whatever you like."
Rias considered for a moment, then wrote with quiet certainty. "Then April 11th—the day we met. How does that sound?"
Arto's expression softened. "Good enough."
Akeno, now measuring his waist, let her hands drift lower than strictly necessary.
Arto glanced down. "Akeno… can you stop touching my butt?"
She gave an exaggerated pout. "I can't help it~ Your cake looks so delicious. In exchange, I'll let you touch mine if you want~"
"I'll pass."
Rias's pen scratched faster. "Is there anything else we need?"
"That's all for now," Rias said firmly. "Akeno! Tongue back in your mouth—no licking!"
Akeno had leaned dangerously close, eyes half-lidded. "Oh, come on~ Just a little taste of my man…"
Rias grabbed her Queen's wrist. "We have enough information. Let's give Arto some privacy."
She began dragging Akeno toward the door.
Akeno waved dramatically over her shoulder. "Goodbye, Arto~ See you at school!"
The door closed behind them—Rias's voice already scolding, Akeno's laughter echoing down the hall.
Arto stood alone in the quiet room, towel still over his shoulder, a faint, bemused smile on his face. He glanced at the mirror—scars, new clothes waiting on the bed, enrollment forms on the desk.
A new name. A birthday. A school to attend. He shook his head, wonder and quiet gratitude in his eyes. "Never thought I'd get a second chance at being… normal."
Arto's POV
The door clicked shut behind Rias and Akeno—their playful bickering fading down the hallway. I sat on the edge of the bed, letting the quiet settle.
First things first: I pulled out the envelope from last night's reward money and counted it again. After the fancy dinner with Akeno (which had been worth every moment, even if the prices made my eyes water), I was down to about 1.94 million yen. A sigh of relief escaped me. Still plenty. But relying on lost-cat bounties wasn't a long-term plan.
Fortunately, the ally contract with the Gremory family included a monthly stipend—200,000 yen. Not lavish, but more than enough when housing, utilities, school fees, and most meals were covered. Rich devils really did live differently.
I glanced at the desk. The beginner's magic primer lay open, surrounded by my scribbled translation notes and the hovering test circles I'd left running overnight. They still spun lazily, stable and patient.
Time to get back to work.
I couldn't just hand them better magic—I wanted to give them something revolutionary. Something this world had never seen. A real "wow" factor that would make my place here undeniable.
So I settled into what I used to call "studying mode": back straight, breathing even, mind sharp and focused. The same state I'd entered before battles that decided the fate of nations.
First step: finish mapping their demonic sigils to my old system.
It was going faster than expected. Many of the basic demonic runes already bent mana in ways eerily similar to certain Abyssgard flow patterns. Minor adjustments here, a rotation there, and they slotted in almost perfectly. Only a handful would need entirely new designs.
I retrieved the crystal lens from its pouch and set it on the small stand I'd improvised from a coffee mug and some books. A thin beam of raw mana—drawn from the ambient energy in the room—passed through it, projecting a straight, shimmering line across the desk.
Perfect baseline.
Now I could craft new sigils, test how they shifted the flow, and refine until the direction and degree matched exactly what I needed.
Hours slipped by unnoticed.
Scratch of pen on paper. Soft hum of mana. Occasional muttered calculations in a language long dead.
Every so often I paused to stretch, rolling shoulders that remembered carrying shields the size of doors, or to glance out the window at the winter sunlight glinting off snow.
This wasn't study for survival.
This was study for the joy of creation—for the chance to share something useful with people who had already given me more than I'd ever dared hope for.
By late afternoon, the first complete translated spell matrix hovered above the page: a simple barrier charm, but constructed in under ten seconds using only three custom sigils and modular flow equations.
I leaned back, allowing myself a small, satisfied smile.
Not bad for a morning's work.
When they saw this—when they realized they could design and cast complex spells on the fly, limited only by imagination and mana reserves… Well. I suspected Rias's eyes would sparkle again. And Akeno....I don't know, she is unpredictable with her....behavior, especially from last night, I didn't expect her to be so....affectionate
[Timeskip: Brought to you by books and notes all over a table]
The sigils were finally complete—every last one mapped, translated, and tested. The desk looked like a battlefield of ink and glowing runes, but the results hovered stably in the air: clean, modular, ready.
Now came the real leap.
During those endless millennia drifting through the Void—nothing but darkness, silence, and my own thoughts—I'd had time to dream beyond survival. Ideas that no war-torn world would ever have let me pursue. Theoretical frameworks. Spell structures that treated mana not as a mystical force, but as a programmable medium.
It was time to test the first one.
I reached for a fresh sheet of paper, pen poised—"Arto darling~… it's time for dinner~"
Akeno's voice floated through the door—sweet, melodic, impossible to ignore.
My hand froze mid-stroke. I love Akeno… I mean—her voice. Yes. Her voice. Of course. What else could I love about her? Her beauty? Her laugh? The way she looks at me like I'm more than a weapon? The way she makes me feel… human?
I shook my head hard, cheeks warming. Focus, old man. I glanced out the window—dusk already painting the sky in deep oranges and purples. Huh. I'd lost the entire day.
Well, progress was progress. Dinner could wait a few more—"Yes, Darling," I called back automatically, standing. "I'm coming—"
The words left my mouth before my brain caught up. The door didn't open. It exploded inward.
Wood splintered. The lock assembly clattered across the floor.
Akeno stood in the wreckage like a violet-eyed goddess of chaos, pupils literally heart-shaped (devil magic, probably), staring at me with unrestrained glee.
"Arto darling~" she sang, stepping over the debris. "I didn't quite catch that. Could you repeat exactly what you said a moment ago, please~?"
I tried—valiantly—to salvage dignity. "I said, 'Yes, Akeno, I'm coming.' That's all."
She glided closer, predatory smile widening. "Nooo, no~ There was a very important word after 'Yes.' Starts with D. Ends with G. Right around the 'arling' part."
I opened my mouth to protest innocence.
From the hallway, Rias's exasperated voice cut through like a blade. "Akeno. Dinner is not Arto. It's downstairs. I asked you to call him down for dinner—not demolish club property."
Akeno didn't even glance back, still locked on me with those heart-shaped eyes.
Rias appeared in the doorway behind her, arms crossed, crimson aura flickering ominously around the ruined doorframe.
She looked at the destruction. Then at Akeno. Then at me—standing frozen in the middle of my rune-covered room, looking like a man who'd just realized he'd accidentally proposed.
Rias pinched the bridge of her nose. "…I'm going to pretend I didn't hear any of that. Dinner. Now. Both of you."
Akeno finally turned, pouting dramatically. "But President~ He called me Darl—"
"Downstairs." Akeno sighed theatrically, then blew me a kiss. "Saved by the King… for now, my darling~"
She sauntered out, hips swaying with extra emphasis. Rias lingered just long enough to give me a look that was half sympathy, half warning. "You're going to need stronger barriers, Arto."
I glanced at the splintered door. "…Noted."
As they disappeared down the stairs—Akeno humming happily, Rias muttering about repairs—I looked back at my desk.
The revolutionary spell matrix still hovered, waiting.
3rd Person POV
Dinner at the clubhouse was a warm, casual affair—miso-glazed salmon, steamed rice, fresh salad, and miso soup still gently steaming in its bowls. Kiba and Koneko had already eaten and retreated (Kiba to finish homework, Koneko to her room with a new chocolate stash), leaving just Rias, Akeno, and Arto at the low dining table.
Akeno sat to Arto's right, occasionally brushing his arm "by accident" while reaching for the soy sauce. Rias sat opposite, watching the two of them with a mixture of fondness and mild exasperation.
Conversation had been light—school preparations, the upcoming term, gentle teasing about uniforms—until Arto set down his chopsticks, expression turning thoughtful.
"Rias," he began, voice calm but carrying that familiar weight of purpose, "can I ask a favor?"
Rias tilted her head, curious. "Of course. What is it?"
"I'd like you to teach me—or give me access to documents—about this world's science. Specifically physics and chemistry. Every available theory. All of it."
Rias blinked. Akeno paused mid-bite, violet eyes flicking to him with sudden interest. Arto continued, meeting Rias's gaze steadily. "I've finished translating my magic system into your demonic sigils. It's ready to share. But before I take the next step… I need to understand how this world functions physically. Laws of motion, thermodynamics, atomic theory, quantum mechanics if you have it—everything. I doubt the fundamental constants differ greatly between my old world and yours, but I need to confirm. Some rules might be subtly different."
He paused, then added with quiet intensity: "I need it for something… extraordinary."
The table went still. Rias set her chopsticks down slowly, blue-green eyes wide. "You want… modern scientific textbooks? Graduate-level theory?"
Arto nodded. "Every aspect. From classical mechanics to the latest models you have."
Akeno leaned forward, smile sharp and intrigued. "Ara ara~ Our ancient knight is planning something big, isn't he?"
Rias ignored the teasing, mind already racing. "You're combining your translated spellcraft… with hard science?"
Arto's lips curved faintly—not quite a smile, but close. "Something like that, it's called magic-tech, something I thought about a lot when I was wandering in the Void, I had time to think and develop that concept, imagine you have machines that runs on mana"
Rias thinks for a moment "I can see that, but it would need a stable mana flow to do that, and it could only be channeled by individuals, we can't get such stable flows from the nature, that's the thing that has been nagging the combinations for decades" Then she looks at him in awe "....Are you saying...."
Arto nods "Yes, I've found a way to stabilize natural mana flows to combine magic and machinery, now I only need the science to complete the picture"
The low dining table fell completely silent.
Chopsticks hovered forgotten in mid-air. Steam from the miso soup curled lazily upward, but neither Rias nor Akeno noticed.
Rias's mind raced—decades of failed devil research, entire conferences dedicated to the instability of ambient mana, countless attempts to merge magical theory with human machinery—all crashing against one quiet sentence from the ancient warrior across from her.
Rias set her chopsticks down with deliberate care, as though any sudden movement might shatter the moment.
"You're telling me… you solved the single biggest barrier to true magitech integration. The problem that's stumped high-class devils, fallen angels, and human magicians for generations."
Arto gave a small, almost apologetic shrug.
Akeno recovered first, leaning forward with sharp, delighted eyes.
"Ara ara~ Machines that run on mana. No batteries, no fuel—just ambient energy, stabilized and harnessed." She tapped her chin thoughtfully. "Imagine the applications. Flight devices that never run out of power. Automated defenses. Household appliances that draw from the air itself…"
Rias's voice was hushed, almost reverent.
"We could revolutionize everything. Transportation. Medicine. Warfare. Daily life." She looked at him, awe and excitement mingling. "You're not just combining magic and science—you're creating an entirely new paradigm."
Arto met her gaze steadily.
"I don't want to assume anything. That's why I need your world's physics and chemistry in full. If the fundamental constants differ even slightly—if gravity or electromagnetic forces behave differently here—the stabilization method might fail or become dangerous. I won't risk it blindly."
Rias stood so quickly her chair scraped loudly against the floor.
"You'll have everything by morning," she said firmly. "The complete Gremory archives—human scientific journals, devil research on mana-material interactions, even classified fallen-angel reports we've… acquired. Textbooks, papers, experimental data. All of it."
[TImeskip: Brought to you by chibi Arto jumping into his book and disappears inside it]
Later that night, long after the dishes were cleared and the clubhouse had settled into quiet, Rias retreated to her private study. The room was warmly lit by a single desk lamp, casting long shadows over shelves of ancient tomes and modern files alike. She activated a secure communication circle on the floor—crimson runes flaring briefly before stabilizing into a shimmering portal of light.
On the other end, in the grand hall of the Gremory estate in the Underworld, Lord Zeoticus and Lady Venelana Gremory appeared—seated in high-backed chairs, expressions attentive.
Rias wasted no time on pleasantries. "Father. Mother. I've found something extraordinary."
Zeoticus raised an eyebrow. "More extraordinary than usual, Rias? You sound… breathless."
Venelana leaned forward slightly. "Tell us, dear."
Rias took a steadying breath. "Two days ago, we rescued a human who single-handedly destroyed six of Sirzechs's most violent mimic chests while exhausted. He's… old. A warrior from another world. He fell through the Void and landed in our trap by accident."
Zeoticus frowned. "And you kept him?"
"He declined reincarnation—for now. He values his human life too much. But that's not the important part."
She paused, eyes gleaming. "He's solved stable ambient mana flow."
Silence...Venelana's teacup paused halfway to her lips.Zeoticus's expression shifted from skepticism to sharp interest. "The barrier to true magitech integration," he said slowly. "The one every faction has chased for centuries."
Rias nodded, standing straight in the circle's glow. "I haven't had the details—he only told me tonight. But he's certain. He's already translated his entire spell system into our sigils. He's asking for full physics and chemistry archives to confirm constants before building anything."
Venelana's eyes narrowed thoughtfully. "That level of confidence… either delusion or genius."
Zeoticus glanced at his wife, then back to Rias. "Bring him into the circle. We want to hear it from him."
Rias hesitated only a heartbeat. "He's asleep—it's late here. But I can wake him. He won't mind."
"Do it," Zeoticus said. "If this is real, we need to know now." Rias stepped out of the circle momentarily.
Minutes later, she returned with Arto at her side. He looked like he'd been roused from deep sleep: hair tousled, wearing a simple loose shirt and trousers, feet bare. His dark blue eyes were still heavy with drowsiness as he blinked at the glowing circle.
"Rias, why did you call me this late?" he asked, voice rough. Then his gaze landed on the two regal figures waiting on the other end. "And who are they?"
Rias exhaled softly. "They are my parents, Arto. In other words… your employers."
The color drained from Arto's face in an instant. He dropped into a deep, formal bow—smooth despite the suddenness, the kind of courtly gesture that belonged to a far older era. "Please forgive me for my insolence, my lord, my lady…"
His head remained lowered, but he turned it slightly toward Rias, whispering in barely concealed panic. "Names...names, Rias....Gimme their names."
Rias leaned close, murmuring just loud enough for him. "Lord Zeoticus Gremory and Lady Venelana Gremory."
Arto straightened immediately, bowing again—this time with perfect protocol. "Lord Zeoticus, Lady Venelana," he said clearly, voice steady despite the earlier panic. "It is an honor. I apologize for my appearance and any offense."
On the other end, Zeoticus's stern expression softened a fraction—amused, perhaps, by the ancient courtesy. "No offense taken," he said. "Rise. We've heard remarkable things about you from our daughter."
Venelana inclined her head gracefully. "Indeed. Rias claims you've solved stable ambient mana flow. A bold assertion."
He lifted his hand. Between his fingers materialized a small, glowing sigil—compact, intricate, and utterly alien to devil eyes. The lines were neither the flowing curves of demonic magic nor the rigid geometry of fallen angel script. They twisted in ways that seemed to defy perspective, yet felt perfectly balanced. "This," he said quietly, "is the core of what I was talking about. The solution to the persistent problem both our worlds have had with mana."
He stepped closer to the circle's edge so the Gremory lords could see clearly. "I call it the Stabilizer. And ironically, its nature lies in something every living being that can absorb mana already does unconsciously."
Rias, Zeoticus, and Venelana nodded—everyone knew the basic truth.
Arto continued, voice calm but carrying the weight of certainty. "We absorb chaotic ambient mana from the environment and convert it into stable internal reserves. That's how we recover mana naturally. But raw environmental mana is too turbulent for direct spellcasting. So how do our bodies tame it?"
Zeoticus's eyes narrowed in realization. "You're referring to the natural biological filter every mana-sensitive organism possesses—the process that refines wild flows into usable ones."
Venelana finished the thought, voice soft with dawning understanding. "That process is extraordinarily complex. No one has ever fully mapped it, let alone replicated it artificially. And you're telling us…"
Rias completed it, staring at the sigil with open awe. "…you've fully understood, optimized, and compressed it into a single sigil capable of processing wild mana at industrial rates."
Arto gave a single, grave nod.
Then, without warning, he raised his other hand.
Darkness bloomed around the study—opaque, velvet-black veil that swallowed light and sound alike, sealing the entire space in perfect isolation. Even the communication circle's glow dimmed slightly, as though muffled.
Rias startled. "You don't need to be that secretive, Arto—"
His face was no longer the gentle, slightly bemused knight she knew. It was hard, serious—eyes scanning corners that shouldn't need scanning. "Someone is definitely watching us right now," he said quietly. "I felt the probe the moment the circle stabilized. Subtle, but there."
He turned to her, voice low and firm. "You should be more careful with world-changing knowledge, Rias."
Zeoticus and Venelana exchanged a sharp glance—surprise giving way to grim agreement.
Venelana's voice carried new respect. "You detected an external scrying attempt through a secured Gremory channel?"
Arto inclined his head. "Old habits. When you've spent centuries as the last line between apocalypse and survival, you learn to feel eyes on you."
Zeoticus leaned forward, all trace of skepticism gone. "Show us, then. Under your veil. We'll trust your judgment."
Within the sealed darkness of the veil, Arto exhaled once—steadying—and let the sigil flare brighter. The Stabilizer rotated slowly in his palm, its alien lines beginning to pulse with faint, controlled light. "The proof," he said simply, "begins now."
With a subtle twist of his wrist, the small sigil expanded—unfolding like a blooming flower of pure mana. Lines stretched, interconnected, and layered until a perfect, intricate mandala nearly two meters across hovered in the air before him. It glowed with a soft, steady azure light—neither demonic red nor holy gold, but something neutral, almost crystalline.
"This is the full version of the Stabilizer," Arto explained, voice calm but carrying the weight of revelation. "A spell designed to tame wild mana. Normally, any spell consumes mana to maintain itself. But the ratio here has been optimized to one in one hundred billion. For every hundred billion units of chaotic ambient mana it processes… only one is needed to sustain the field."
The change was immediate—and breathtaking. Inside the veil, the air itself seemed to hum. The invisible, ever-present turbulence of environmental mana—normally a roiling storm devils felt instinctively—smoothed into perfect, laminar streams. Orderly. Predictable. Stable.
Rias's eyes widened. She could feel it: the chaotic eddies that always tugged at her power were gone. The mana around her flowed like calm water, ready to be shaped. Zeoticus and Venelana leaned forward on the other end of the circle, expressions shifting from cautious interest to open astonishment. "You can actually cast spells in here without using your own reserves," Arto said, turning to Rias. "Try it."
Rias hesitated only a heartbeat. She raised her hand—no incantation, no draw from her personal well—and simply willed a small sphere of crimson Power of Destruction into existence. Normally, even a basic orb would require a flicker of her own mana to form and maintain. This time… nothing.
The sphere materialized instantly, hovering above her palm, perfectly stable and drawing sustenance solely from the tamed ambient flow. It glowed brighter than usual—cleaner, more potent. Rias's breath caught. She let it grow—larger, denser—until it was the size of a basketball, spinning slowly with contained annihilation. Still no drain on her reserves.
On the other side of the circle, Venelana's teacup clattered softly against its saucer. Zeoticus's voice was hushed. "…Impossible."
Arto allowed himself a small, satisfied nod. "This is only the beginning. With proper physical laws confirmed, I can refine it further—scale it, shape it, integrate it into machinery. Endless power. Clean. Stable. Unlimited."
He met the Gremory lords' eyes directly. "I don't ask for trust on words alone. Give me the archives. One week. I'll deliver a working prototype—something you can hold, test, and verify." Venelana recovered first, composure returning like a cloak. "You shall have everything you need. By dawn."
Zeoticus added, voice firm but laced with unmistakable excitement. "And if your prototype functions as this demonstration suggests… the Gremory clan will stand fully behind you. Protection. Resources. Whatever you require."
Rias couldn't hide her triumphant smile. Arto inclined his head—respectful, but not subservient. "Thank you, Lord Zeoticus. Lady Venelana."
The veil dissolved as smoothly as it had formed, ambient mana returning to its natural chaos the instant the Stabilizer collapsed. The communication circle dimmed. Rias turned to Arto, eyes shining. "You just changed everything."
Arto rubbed the back of his neck, the serious mask slipping back into quiet humility. "I hope so. For the better."
[Elsewhere]
In a sleek, modern apartment overlooking Kuoh's quiet nighttime streets, Sona Sitri stood by the window, phone pressed to her ear. The city lights reflected in her pink oval glasses, but her expression was anything but relaxed.b"I see. Thank you, Spy," she said coolly. "But remember our deal."
On the other end, a voice like honeyed silk replied. "It's a pleasure working with you, Miss Sona. As for our deal—the intel will not be on the display shelf. I've received the payment. You're welcome."
A soft laugh. "And about your offer to me… I must decline."
The line went dead. Sona lowered the phone, exhaling slowly. "That woman," she muttered. "Always knows before I even open my mouth."
She turned from the window, gaze sharpening. "But it's all right. I'll come back with another deal."
Her eyes drifted to the distant silhouette of the old school building—the Occult Research Club clubhouse. "So this is what you've been hiding from me, Rias."
Her voice was quiet, but carried the weight of someone who disliked surprises—especially from supposed allies. "We rule this town together. That means intel must be transparent between us. But with this…" She adjusted her glasses. "I know you're protecting his knowledge. And you'll stop any attempt I make to recruit him for my peerage."
A pause. Sona's lips pressed into a thin line. She dialed again—this time a secure line. "Mother. Father," she said the moment the connection opened. "Something urgent has come up. We need to have a talk with the Gremory clan about… a classified asset."
On the other end, her parents' voices overlapped briefly—curious, concerned, attentive. Sona's gaze remained fixed on the distant clubhouse lights. "One that could change everything," she added softly.
[Arto's study]
Arto closed the door behind him with a soft click, the sound echoing slightly in the quiet room. The lamp on his desk still burned low, casting warm light over the scattered notes, the open primer, and the faint afterglow of the sigils he'd been testing earlier.
He took two steps toward the desk—then stopped. The air felt… off. Not hostile, but watched.
His gaze flicked to the notebook he'd left open: the page with his latest sigil sketches, equations, and the Stabilizer's core formula. A tiny ripple shimmered just above the paper—barely perceptible, like heat haze over asphalt.
Arto sighed, long and tired. "It's encrypted my way," he said aloud, voice calm but carrying a clear edge. "Don't try to read it."
He reached out with casual speed, fingers closing around something invisible. A faint shimmer of silver light revealed what he had caught: a disembodied, translucent eye, no larger than a marble, floating mid-air. Beside it, almost completely hidden until now, hovered a delicate, shell-like ear.
Both constructs pulsed once, weakly, as if startled to be discovered. Arto held the eye up to his own face, studying it without anger—just quiet recognition. "We'll meet again… soon."
His voice was low, almost gentle, but the promise in it was unmistakable. He didn't crush the constructs. Instead, his free hand flickered with a brief, intricate spell—old, precise, carrying the weight of centuries. The eye and ear trembled, then folded in on themselves like paper caught in a sudden wind, collapsing into two small motes of light that winked out harmlessly.
The room felt cleaner. Lighter. The oppressive sensation of being observed vanished. Arto exhaled through his nose, shoulders dropping a fraction. He glanced at the notebook one last time, then reached over and closed it. The Stabilizer matrix he'd been refining earlier had been safely tucked into a separate, encrypted layer—nothing critical had been exposed.
Still… the watcher had been bold enough to probe a Gremory-secured channel and his personal workspace on the same night. That took skill. And guts.
He shook his head once, a faint, wry smile tugging at his mouth. "Busy first week," he muttered to himself.
He turned off the lamp, leaving the room in darkness save for the soft winter moonlight filtering through the window.
He glanced at the bed—tempting, but sleep was gone now. Adrenaline and leftover focus buzzed under his skin. Half-charged, as he used to call it back in the legions. Might as well use it.
He pulled the chair out, sat at the desk, and opened the notebook to a fresh page.
[Timeskip: Brought to you by chibi Arto sitting at his desk until chibi Rias came and pulls him away, there were signs of protest but no use]
Time had lost all meaning.
Arto's room was lit only by the soft glow of the desk lamp and the occasional flicker of hovering test sigils. Pages of the primer lay scattered—covered in dense notes, cross-references, and newly drawn translation matrices. His handwriting, precise even in exhaustion, filled every margin. Empty tea cups—courtesy of a sleepless summoning of minor refreshment spells—stood in a neat row at the edge of the desk.
He was deep in the flow state, pen moving without pause, when a soft, sleepy voice broke the silence. "Arto… what are you doing this early in the morning?"
He blinked, pen slowing. Turning in his chair, he saw Rias in the doorway—hair tousled from sleep, wearing a loose silk nightgown that fell to mid-thigh. Her eyes were half-lidded, but concern sharpened them as she took in the scene: the littered desk, the hovering runes, and Arto himself—shirt sleeves rolled up, eyes bloodshot but bright with focus.
Arto glanced groggily toward the window. The first pale gold of dawn was creeping over the horizon. "It's morning already…" he muttered, more to himself than her.
Rias caught it instantly. She stepped fully into the room, arms crossing as her voice took on that familiar mix of worry and exasperation. "Arto. Don't tell me you stayed up all night working at your desk."
He set the pen down at last, rolling his shoulders with a wince. The motion made him aware of how stiff he was—hours hunched over paper, mana thrumming constantly through his hands. "…Maybe."
Rias sighed, walking over and placing a hand on his forehead as if checking for fever. "You didn't sleep at all, did you?"
"I meant to take a break," Arto admitted, voice rough from disuse. "But the translations were flowing well. And then the stabilization ratios needed refining. And then—"
She cut him off gently, fingers brushing damp hair from his forehead. "And then you forgot the world existed. I know the look."
Arto managed a tired half-smile. "Old habit. When inspiration strikes on the battlefield, you don't sleep until it's captured."
Rias's expression softened, but she didn't let him off the hook.
"It seems that I have to put you to bed on my own."
Before he could protest, Rias stepped right up to the desk chair. With effortless strength—devil heritage making her far more powerful than her graceful figure suggested—she slid her arms around his waist and lifted him clean off the seat.
Arto's eyes widened in pure, startled surprise. For a split second he went rigid, arms hovering uselessly in the air, as though his brain hadn't quite processed that a woman half his size could hoist him like he weighed nothing.
"Rias—?"
She didn't give him time to finish.
With a playful little toss, she deposited him onto the mattress. He landed with a soft bounce, still wide-eyed. Before he could sit up, Rias followed—climbing onto the bed and immediately wrapping herself around him.
Her arms looped across his chest, holding him firmly against her. One leg slid between his, intertwining until there was no escape. Her head settled on his shoulder, crimson hair spilling over his collarbone like warm silk. She pressed close—soft, warm, and unapologetically possessive.
"Sleep a little, Arto," she murmured against his neck. "You told me you value this human life. Dying from lack of sleep isn't noble enough for me to press that Knight piece into your chest."
Arto lay frozen for a heartbeat—every muscle tense, breath shallow. He could feel her heartbeat against his side, steady and calm. The faint scent of her shampoo mixed with the clean soap from his own shower. Her body molded against his perfectly, as though she belonged there.
Slowly—very slowly—the tension began to drain from him.
He exhaled, long and shaky.
"…You're impossible," he muttered, but there was no heat in it. Only quiet surrender.
Rias smiled against his shoulder, eyes closing.
"I know. Now hush. Sleep."
She tightened her hold just a fraction—enough to remind him he wasn't going anywhere.
Arto stared at the ceiling for another minute, listening to her breathing even out. The weight of her arm across his chest, the warmth of her leg tangled with his, the gentle rise and fall of her body against him—it was all so… ordinary. So human.
He hadn't been held like this in millennia.
His eyelids grew heavy.
The last thing he felt before sleep claimed him was Rias's fingers tracing idle, soothing circles on his chest—right over the spot where his heart beat steady and strong.
Rias's POV
Darkness.
Not the comforting kind that comes with closed eyes or a power outage—no, this was absolute, suffocating, living darkness. It pressed against my skin like cold oil, heavy enough to make every breath feel borrowed.
I woke up in it. No warning. No transition. One moment I was curled against Arto's warm chest, listening to the steady rhythm of his heartbeat as exhaustion finally claimed him after his all-nighter. The next… nothing.
My devil eyes adjusted instantly—crimson glow illuminating my own hands, the curve of my arms, the fall of my hair—but beyond that faint bubble of self-light, the void refused to yield. No walls. No ceiling. No floor texture beyond unnaturally smooth, featureless stone that stretched forever.
I stood slowly, wings half-unfurling on instinct. The air tasted stale, metallic, like old blood left to congeal. My heart began to hammer.
"Hello?" My voice echoed strangely—swallowed almost immediately, as if the darkness had teeth.
Nothing answered.
I reached for the peerage bond—Akeno? Kiba? Koneko? Arto?—and felt only empty silence. Not even static. The connection was gone, severed clean.
Panic rose like bile in my throat.
No. Stay calm. Think.
I dropped to one knee, pressing my palm flat against the ground to steady myself. Deep breath. Another. In through the nose, out through the mouth. The way my mother taught me when I was small and the weight of the Gremory name first started pressing down.
Last memory: pinning Arto to the bed after he refused to sleep. Wrapping myself around him. His quiet surrender. His warmth. Then… nothing.
Questions swirled.
Where am I? How did I get here? Where is Arto?
I forced myself to stand again. Panic wouldn't help. Directionless wandering wouldn't either. But standing still felt worse—like surrendering to whatever this place wanted.
I chose a direction at random and walked.
One step. Two. The ground never changed. No slope, no cracks, no sound but my own heartbeat and the soft tap of my bare feet.
Minutes bled into what felt like hours. My legs trembled—not from fatigue, but from the creeping dread that I might walk off an unseen edge into oblivion. My wings twitched, wanting to fly, but the memory of endless upward nothing earlier kept them folded.
Eventually, exhaustion forced me to sit again. I hugged my knees, wings wrapping around myself like a cocoon.
Think, Rias. You're the heiress of destruction. You don't break.
I tried to recall every teleportation mishap, every dimensional trap I'd studied. Nothing matched this sensory deprivation. No ley-line interference. No sealing ward signature. Just… absence.
And Arto was missing. That hurt worse than the dark. I stood once more. Walking was better than waiting to be consumed. I opened my wings and launched upward—higher, higher—until vertigo made me stop. Still nothing. Just black in every direction.
I landed. The impact barely echoed. Then I felt it. A pressure at my back—massive, malignant, hungry. Instinct screamed. I threw myself forward.
BOOM.
The ground where I'd stood shattered. An axe larger than my entire body embedded itself in the stone, sending shockwaves up my legs. I rolled, came up in a crouch, and faced it.
The creature was nightmare-made-flesh. Pale, bloated skin stretched over a grotesque, muscular frame. Glowing red eyes set in a face that had no right to exist. One arm ended in claws; the other fused into the haft of that monstrous axe. A distended belly hung low, as though stuffed with the remains of everything it had ever killed.
It didn't roar. It just advanced—slow, inevitable. I fired Power of Destruction without thinking. Crimson orbs streaked through the dark and struck true—burning craters across its chest. It staggered, black ichor oozing from the wounds.
But it kept coming. I retreated, firing again and again. The burns deepened. Blood flowed. Its movements slowed.
I focused—joints, eyes. One orb took an eye. It howled—a sound like tearing metal.
Blind, it swung wildly. I closed the distance. A massive orb of concentrated Power formed between my palms—larger than my head, swirling with annihilating force.
I hurled it. The creature's head vanished in a crimson detonation.
The body toppled. Silence. Victory trembled through me—shaky, adrenaline-fueled.
Then more presences. Dozens. Hundreds. Red eyes opened in the dark, surrounding me in a tightening circle.
Axes raised. I shot skyward, wings beating furiously.
Below, the horde collided in confusion—blades and claws tearing into each other. Some fell, crushed by their own kind.
Hope flickered. Then—sound. Metal on metal. Explosive impacts. Roaring wind.
From my right. And with it… light. Dim at first—blue-white, flickering like a distant star. But growing. I banked hard, flying toward it at full speed. The closer I got, the clearer the scene became.
Not an army. One man. A lone figure in battered silver-and-blue armor, moving like a storm given form.
Magic circles flashed into existence and vanished in heartbeats—barriers, blades of light, explosive bursts. Slashes of pure force carved through waves of darkness, parting the tide like a ship through water.
Monsters—hundreds, thousands—surged against him. He held. Alone. My breath caught.
That armor. Those movements. The way he fought—not with devilish grace or angelic precision, but with raw, unrelenting experience...Arto.
I flew faster than I ever had, wings cutting through the thick, oppressive darkness. The dim blue light grew brighter with every desperate beat—Arto's light. My light now, too.
I landed hard behind him, boots skidding on the unseen ground. The clash of steel and monstrous roars was deafening up close. He was a whirlwind—armor flashing, sword singing, magic circles blooming and vanishing like deadly fireworks.
He didn't hear me land.
His blade whipped around in a vicious arc—straight toward my neck. There was no time to shout, no time to dodge. I froze, eyes wide, preparing for the end. The sword stopped. A few millimeters from my throat. So close I felt the cold kiss of steel.
Arto's eyes—dark blue even through the helmet's visor—widened in recognition. "Rias!?" His voice cracked with shock and something rawer. "Is that you? How did you get here?"
The tears I'd been fighting spilled over. "It's me, Arto," I choked out, voice trembling. "It's really me… I don't know how…"
A guttural roar cut me off. "Careful!!!"
His arm snapped around my waist like iron, yanking me hard against his chest. We spun together—he shielded me with his body as a massive claw raked the air where I'd stood. With his free hand, he thrust forward. A blazing spear of blue-white mana erupted from his palm, punching a perfect, smoking hole through an entire line of charging monsters.
His armor was soaked—blood, both black and red, streaming from countless cuts. Gashes marred the plates; one pauldron hung loose. His breathing was ragged, labored, every exhale a rasp.
Yet he didn't falter.
He released me only long enough to plant himself between me and the horde. "Cover me!" he roared. Magic circles—dozens of them—ignited around him in a corona of azure light. They flared, feeding power into his blade as he launched himself forward like a comet into the fray.
The monsters met him in a wave of claws and axes.
I wiped tears away with the back of my hand, crimson aura surging. "On it."
Power of Destruction bloomed in my palms—larger orbs than I'd ever formed in training, fueled by fear and fury and something fiercer.
I unleashed them into the tide at his back.
Where his precise, relentless strikes carved paths, my annihilation erased entire ranks.