3rd Person POV
Akeno stirred slowly in the tangled warmth of sheets and limbs. The king-sized bed in the master suite of the new mansion felt almost too big some nights, but last night it had been exactly the right size—three bodies pressed close, sweat-slick skin cooling together as exhaustion finally claimed them. Arto's Dark Arena had been especially cruel this time: shifting labyrinths of obsidian thorns, shadow-wraiths that wore their own faces, gravity wells that tried to crush bone and will alike. They had fought valiantly—Rias's Power of Destruction carving crimson paths, Arto's blue-flame sword cleaving through nightmares, Akeno's lightning chaining between them like a protective web—and they had won. But victory always left bruises.
She sat up carefully, spine protesting with a dull ache that radiated down her lower back and thighs. Naked, skin still faintly flushed from the dream-battle's afterglow, she stretched both arms overhead—shoulders popping, wings briefly flickering into existence before folding away again. The motion pulled at sore muscles in a way that was almost pleasant, like proof she was still here, still whole.
Arto slept on his back beside her—chest rising and falling in deep, even rhythm, one arm flung across Rias's waist. Rias herself was curled against his side, face tucked into the crook of his shoulder, crimson hair spilling across his collarbone like spilled wine. They looked peaceful. Untouched. As though the Arena had never reached them.
Akeno's gaze softened. She reached across Arto's chest—careful not to wake either of them—and retrieved the small, matte-black burner phone from the nightstand. Habit now, as automatic as breathing. The screen lit under her thumbprint.
Loreen Ravenna (her alias) Last message from Elias – 04:12
She opened the thread.
Elias (04:12): I put the gun back in the drawer tonight. Didn't even look at it for long. First time in months I didn't sit with it in my hand until dawn. Thank you for the reminder yesterday. I still hear her scream sometimes when it's quiet… but your words were louder. Good night, Loreen. Or good morning, wherever you are.
Akeno's throat tightened. She typed quickly—thumbs soft on the screen.
Loreen Ravenna (06:47): Good morning, Elias. I'm glad the drawer won last night. That's a victory worth celebrating, even if it feels small. I woke up sore today—bad dreams, old wounds acting up. But the soreness reminds me I'm still here. Still breathing. Still fighting. You're still fighting too. Keep fighting. One drawer at a time.
She hit send. Then leaned back against the headboard, phone cradled against her chest, and simply breathed.
Arto stirred beside her—eyes cracking open, dark blue and sleepy. He didn't speak. Just watched her for a moment, then reached over and brushed a strand of black hair from her face. "Morning," he murmured, voice gravel-rough from sleep. Akeno turned her head—smiled softly. "Morning."
Rias mumbled something incoherent and burrowed deeper into Arto's side. Akeno's phone buzzed—soft, once.
Elias (06:51): Sore here too. Old scars. Old guilt. But you're right. Still breathing. Still fighting. Thank you for checking in. Feels like… someone cares whether I make it through the day. I do too, you know. Care whether you make it through yours.
Akeno's eyes stung—sudden, sharp. She blinked rapidly, then typed back with trembling fingers.
Loreen Ravenna (06:52): I care. More than you know. We'll keep breathing together, okay? One day at a time.
She sent it. Then set the phone face-down on the sheets and curled into Arto's other side—forehead resting against his shoulder, one hand finding Rias's across his chest. Arto's arm settled around both of them
[On the way to Kuoh Academy]
The walk to Kuoh Academy felt lighter than usual that morning—sun high, cherry blossoms drifting lazily, the group moving in their familiar loose formation: Rias, Akeno, and Nami leading the chatter up front, Arto and Kiba trailing a half-step behind like quiet knights escorting royalty. Koneko had already peeled off toward her junior high.
Conversation had long since drifted away from upcoming exams (everyone knew they'd ace them; the real question was by how much). Instead, the topic had turned to the one thing every student craved at the end of a grueling semester: Vacation.
Rias walked backward for a few steps so she could face everyone, arms spread like she was already picturing the itinerary. "So it's settled: first stop is mandatory—my family's estate in the Underworld. Father already sent the formal invitation. We'll spend at least a week there. Full tour, feasts, probably some embarrassing childhood stories from Mother, and Sirzechs will definitely try to challenge you all to a 'friendly' sparring match he'll pretend isn't serious."
Akeno laughed, twirling a lock of hair around her finger. "I'm more worried about Serafall turning it into a magical-girl boot camp. Last time she visited she tried to make me wear a frilly costume for 'family bonding photos.'"
Nami snorted without looking up from her phone. "I'll pay to see that. Actually—no, I'll charge admission. We could make a fortune."
Rias rolled her eyes fondly. "After the Underworld leg, we have the rest of the month free. Beach? Mountains? Hot springs? We can do all of it. No missions unless something urgent comes up. No training deadlines unless Arto decides to be evil again."
Arto, walking with hands in his pockets, gave a small huff. "I've already stretched the schedule. You're getting actual downtime. Use it." Kiba smiled quietly beside him. "I've never had a real vacation before. Not one that wasn't… tactical rest between deployments."
Rias spun back around to walk forward, linking arms with Akeno. "Then we're fixing that. Private beach house in Okinawa—Nami already scouted the listings. Mountain ryokan with open-air baths in Nagano. Maybe even a quick hop to a human-world ski resort if we want snow in summer—perks of devil teleportation."
Nami finally looked up from her phone, eyes gleaming. "And the best part? We can all pull our wallets out and actually pay for things. No more 'let Rias cover it because she's the princess' nonsense. Between the stray-hunting bounties, the joint mission payouts, and the little royalty drips already coming in from the Simulation Room contracts… we're all sitting on actual fortunes."
She tapped her phone screen. "Speaking of which—starting next week I'm launching a mandatory money-management class right alongside magic lessons. Budgeting, investment basics, tax loopholes in the human world vs. Underworld, how to spot scam artifacts… the works. Fee is—"
Arto's head snapped toward her. Nami met his glare, grin widening. "—free of charge, obviously. How could I be such a heartless person to put a price on things for my family?" Rias laughed brightly. "You're only heartless when someone tries to short-change you on royalties."
"Exactly," Nami said primly. "Family gets the VIP pass. Everyone else pays through the nose." Kiba chuckled softly. "I'll take notes. Never had to manage personal finances before." Arto clapped him on the shoulder once—light but solid. "You'll learn fast. Nami's ruthless but fair."
They reached the school gates. Students streamed past, some glancing curiously at the group (the "VIP table" crew always drew eyes), but no one interrupted. Rias turned to face everyone, walking backward again. "So—Underworld first. Then we vote on the rest. Beach? Mountains? Hot springs? All of the above?"
Akeno raised her hand like a schoolgirl. "All of the above. And matching yukata for the onsen trip. Mandatory."
Nami cackled. "I'm already designing the group fund spreadsheet." Arto just shook his head—fond, resigned, quietly content. "Deal."
[Kuoh Academy]
At school, Rias and Akeno had been unusually focused lately—not just on lectures or upcoming exams, but on something quieter and more personal. During breaks, they often sat together in the library corner or the rooftop (when no one else was around), heads bent over shared notebooks filled with dream-journal entries, symbol charts, reality-check logs, and hand-sketched "dreamscape blueprints." Robin occasionally joined them remotely—sending annotated PDFs or short voice notes with precise instructions on stabilizing dream lucidity or constructing persistent environments.
Arto noticed, of course. He noticed everything about them.
One afternoon, during a free period in the empty occult research club room, he finally leaned over the table where Rias was carefully shading a glowing archway on her sketchpad. "Why lucid dreams?" he asked quietly, voice low enough that only she and Akeno (sitting beside her) could hear. "You two used to say sleep was the only time you could truly rest."
Rias didn't flinch or hide the page. She set the pencil down and met his gaze steadily. "Because every time Akeno and I sleep beside you, we get pulled into the Dark Arena," she answered without preamble. "No warning. No choice. Just… there. Fighting. Bleeding. Surviving. We win—most nights—but it's still war. Every night."
Akeno nodded, fingers tracing the edge of her own notebook. "And the Arena learns. Even when we win, it catalogs every new move, every adaptation, every weakness we reveal under pressure. The next training session in Sector 1 becomes harder because of what we showed it while we slept."
Rias leaned forward slightly, voice dropping even lower. "So Robin's been teaching us how to build our own dreamscapes—stable, persistent places we control. A sanctuary we can retreat to the moment sleep begins. A place the Dark Arena can't reach unless we allow it. Somewhere safe, beautiful, ours. We want to pull you there too, Arto. Permanently. So you don't have to wake up every morning tasting blood and ozone."
Arto's expression didn't change much—still calm, still attentive—but something flickered behind his eyes. Recognition. Resignation. A trace of old grief. "I've tried that," he said quietly. "More times than I can count. Lucid dreaming. Memory palaces. Constructed paradises. Astral projection anchors. Every technique the old grimoires and the new psychology texts ever described. None of them held."
He looked down at the sketch on Rias's pad—the glowing archway, the soft horizon beyond it—and his voice grew softer still. "The Dark Arena isn't a place of wonders. It's a survival mechanism. It's been festering inside me for thousands of years. When I sleep, wonders and ideas mean almost nothing next to the instinct that says stay alive, stay alert, stay ready. Survival drowns everything else out. I can visit beautiful places for a few minutes… but the Arena always pulls me back. Always."
He met Rias's eyes—then Akeno's—open, unflinching. "If the two of you can build a sanctuary strong enough to hold me there… permanently… I would be grateful. More than grateful. But if you can't—if the Arena still claims me every night—then maybe it's time you stopped sleeping beside me."
The words landed like stones in still water. Rias's hand clenched around her pencil. Akeno's wings flickered into visibility for half a second—reflexive, defensive—before vanishing again. Neither of them spoke immediately. Then Rias reached across the table—took both of Arto's hands in hers. "No," she said—firm, quiet, unshakable. "We don't stop sleeping beside you. We don't stop sharing your bed. We don't stop waking up tangled together. That's not negotiable."
Akeno leaned in from the other side—her hand covering Rias's and Arto's. "We're not abandoning you to the Arena every night just because it's hard," she said, voice thick but steady. "We're going to build something strong enough to hold all three of us. Somewhere the Arena can't reach. Somewhere you can rest—really rest—for the first time in millennia."
Arto looked between them—searching their faces. "You understand what you're saying?" he asked quietly. "If it fails—if I still get pulled every night—you'll wake up bruised and bleeding beside me. Again. And again." Rias squeezed his hands tighter. "Then we'll wake up bruised and bleeding beside you. Again. And again. Until we get it right."
Akeno's smile was small, fierce, tear-bright. "We've fought worse things than your nightmares, darling. And we always win. Together." Arto exhaled—once, long, ragged. Then he bowed his head until his forehead rested against their joined hands. "You two are the best"
[Timeskip: Brought to you by chibi Rias and chibi Akeno dreaming together]
After the final bell rang and the hallways of Kuoh Academy emptied into the golden afternoon light, Rias and Akeno found Arto exactly where they expected: sitting alone on the low stone wall behind the old school building, one leg dangling, the other bent so his forearm rested on his knee. He was reading something on his phone—probably Celine's overnight diagnostic logs from Sector 3—but he looked up the moment their footsteps reached him.
Both girls stopped in front of him, arms crossed in perfect sync, expressions somewhere between determined and playfully mutinous. Rias spoke first. "We're ready." Akeno nodded once—sharp, decisive. "For the Spellcrafting Formulas teacher test."
Arto slowly lowered his phone. His expression didn't change much—still calm, still faintly amused—but his eyes sharpened. "You finished the book."
"Not just finished," Rias corrected. "Mastered. Every theorem. Every proof. Every edge case. We can apply them in combat, in crafting, in theory debates. We've been running mock lessons with each other for two weeks. We're ready."
Akeno tilted her head, violet eyes gleaming. "And we're tired of Nami lording that certificate over us every single breakfast. She's still smug about homework immunity. We want in." Arto studied them for a long moment—first Rias, then Akeno—then exhaled through his nose in what might have been a laugh or a sigh. "Alright," he said quietly. "You can take the test."
Both girls straightened—small triumphant smiles breaking through. "But I'm warning you now," Arto continued, voice dropping into that calm, unhurried register that always made people listen harder. "It won't be simple. It won't be kind. And it won't be quick."
He held up one finger. "Part one: improvement. You each choose one formula—or a small cluster of related formulas—from the book. You will propose meaningful upgrades. Not cosmetic tweaks. Real, provable enhancements—better mana efficiency, faster casting time, greater stability under stress, reduced backlash, whatever you can mathematically and practically defend. You submit your revised version with full derivation, test cases, and comparison metrics."
Second finger. "Part two: advanced problem set. Thirty sheets. Core structure questions—magical constants under relativistic mana conditions, multi-layer intention interference, resonance collapse in high-entropy environments. You have exactly 120 minutes. No notes. No calculator. Pen and paper only."
Third finger. "Part three: the toddler test. After you finish, you will explain your improvement—and one randomly selected advanced problem—to a simulated five-year-old. Using only language a child can understand. No jargon. No equations. Just clear, simple concepts. If the sim-toddler can repeat the main idea back to you correctly, you pass. If not… you fail."
He let that sink in. "That's how Nami earned hers. She didn't just improve one formula—she optimized mana consumption across the entire book. Every single page. She submitted revisions that shaved an average 14.7% off casting costs without sacrificing power or stability. That's why she's smug. She earned it."
He glanced toward the school building—where Nami was probably already lounging in the student council room, feet up, basking in her homework immunity.
"Robin earned hers through sheer volume and depth. She's sent me over two hundred pull requests since I gave her access to the Git repo. Some were small clarifications. Some rewrote entire chapters. Our late-night magical debates sometimes lasted until dawn. She's extraordinary. That certificate wasn't a gift. It was payment for work most professors couldn't do."
Arto looked back at Rias and Akeno—eyes steady, unyielding, but warm underneath. "So if you want the same status—the right to use the Git system, to submit changes that become canon, to teach the book with my authority—you earn it the same way. No shortcuts. No favoritism. Just proof."
Rias met his gaze without flinching. "When?" Arto smiles "It's on you, have you two decided yet?" he asked quietly, voice pitched for her and Akeno alone. "What you're going to improve in the book."
Rias blinked—then exchanged a quick look with Akeno. "Not completely," she admitted. "We've narrowed it down to three candidates—intention-indexing under high-latency conditions, resonance collapse in multi-caster arrays, and the emotional anchoring chapter you mentioned last time. But we're still debating which one has the most room… and which one we can actually prove better."
Akeno nodded, tucking a strand of hair behind her ear. "We want it to be meaningful. Not just tweaking numbers for the sake of tweaking." Arto gave a small nod—approval, not judgment. "Then take another week. Think. Test small prototypes in Sector 1 if you need real-world feedback. No rush. The test isn't going anywhere."
He glanced between them—eyes steady, voice dropping softer. "But I want you to understand something clearly before you start." Rias tilted her head, listening. "That book—Spellcrafting Formulas—is not sacred. It's not perfect. It's not the final truth carved in stone. It's the work of thousands of years, thousands of minds, thousands of mages and scientists of the Abyssgard Legion… and even then, it was never meant to be untouchable. They improved it constantly. Challenged it. Broke it. Rebuilt it better. That's how they survived. That's how they kept the Abyss at bay for so long."
He looked at Rias specifically now—knowing how much she revered his words, his knowledge, sometimes to the point of hesitation. "The version you studied—the one Robin and Nami first used—was my first rough translation. I did it in a few days to make it usable in this world. Mostly swapping constants, adjusting mana-density ratios, renaming a few operators so the logic would map to your system. I didn't dive deep into the core axioms. I didn't re-derive every constant from first principles here. It was scrappy. Quick. A stopgap."
He let that sit for two steps. "And yet… those formulas still worked. From 'fine' to 'well,' even with my hasty adaptation. That alone should tell you how strong the foundation is. The Legion built something enduring. Something that can survive being dragged across worlds, across systems, across thousands of years of refinement and still hold up."
His voice grew quieter—almost gentle. "So to the certain someone who admires me too much…" he gave Rias the faintest, fondest smile, "…you shouldn't treat my words or that book like sacred relics to be stored in beautiful glass boxes. You should question them. Challenge them. Break them if you have to. Look for cracks, for outdated assumptions, for places where this world's magic bends differently than Hell's ever did. Improve it. That's the only way to honor the people who came before me—the scientists and mages who bled and died so their work could reach the right hands, for the right purpose."
Rias's eyes shimmered—sudden moisture she blinked away quickly. Arto reached over—squeezed her hand once. "The Legion never stopped refining. Neither should we. Their legacy isn't a perfect, untouchable book. Their legacy is the act of never being satisfied. Of always reaching for better. That's what made them strong enough to guard the Abyss for so long. That's what will make you strong enough to keep guarding whatever comes next."
He looked at both of them—Rias and Akeno—then at Nami and Kiba a step behind. "So take the week. Think hard. Test rigorously. Then come back with changes that make the book better. Not for my ego. Not for a certificate. For them—the ones who wrote the first lines in blood and hope. And for the ones who'll need those lines after us."
Robin slipped into step beside them just as the mansion gates came into view—her usual quiet arrival, coat fluttering slightly in the late-afternoon breeze. She didn't announce herself; she never did. But Rias and Akeno both felt her presence at the same instant and turned their heads in perfect sync.
Robin's smile was small, knowing. "I heard about the teacher test," she said without preamble, voice warm but carrying that familiar edge of quiet authority. "I'm glad. Really glad. Reaching for the instructor level in Spellcrafting Formulas means you're not just using the knowledge anymore—you're claiming it. Shaping it. That's the highest compliment you can pay the book… and the people who bled to write the first lines of it."
Rias straightened a little—pride flickering in her eyes. "We're ready," she said firmly. "Or… we will be." Akeno nodded, fingers brushing the strap of her school bag where her annotated copy of the book was tucked. Robin's gaze softened further. "It won't be simple," she warned gently. "The grading council won't be just Arto this time. It'll be Arto, me… and Nami."
Nami—walking a few steps ahead—immediately spun on her heel without breaking stride, walking backward now so she could face them. Her smirk was instant, wide, and utterly wicked. "I'll make sure you never pass~" she sang, voice dripping with exaggerated menace. "One typo in your derivation? Fail. One mana-flow efficiency gain below 8%? Fail. One explanation that makes the toddler sim go 'huh?' instead of 'ohhh!'? Glorious, spectacular fail."
Rias's mouth dropped open in betrayal. "Nami! You're pulling personal business into academic matters!" Nami shrugged—still walking backward, arms spread like she was conducting an orchestra of chaos. "Hey, I didn't make the rules. I just enforce them with extreme prejudice. Besides—" she pointed at both girls with finger-guns "—you two have been mocking my 'eternal shield' certificate for weeks. Turnabout is fair play."
Arto and Robin exchanged a single glance—then both turned toward Nami, expressions identically calm and unamused. Arto spoke first—voice low, even, carrying that quiet finality that always made Nami's smirk falter just a fraction. "Be professional in the test, Nami."
She blinked—footsteps slowing. "If you don't," Arto continued, "Robin will revoke your certificate. Again. And this time it won't be temporary." Robin nodded once—red pen already tapping against her palm like a metronome of doom.
"You remember what happened last time," she said mildly. "You promised to bring the second class—Sona's peerage minus the three who were already caught up—up to speed with the main group. You were too busy counting zeroes from the Simulation Room contracts. You missed three sessions. You let three chapters slip. I had to step in and reteach everything myself."
Nami's backward walk finally stopped. She looked between Arto and Robin—then at Rias and Akeno, who were now openly grinning. Robin's voice stayed perfectly even. "You earned that certificate through real work—brilliant work. Don't taint it by turning the test into a personal vendetta. Grade fairly. Argue honestly. If their improvements are valid, say so. If they're not, explain why. But do it like the teacher you claimed to be… not like the CFO who's still salty about losing her homework immunity."
Nami stared at them for a long second. Then she huffed—dramatic, theatrical—and spun back around to walk forward again, shoulders slumping in mock defeat. "Fine. Professional. No vendettas. I'll be the picture of academic integrity." She threw a look over her shoulder—smirk creeping back despite herself. "But if your improvements are trash… I'm still going to enjoy saying it."
Rias laughed—bright, relieved. "Deal." Akeno looped her arm through Rias's—then reached back to tug Arto's sleeve. "You'll be fair too, right, darling? No favoritism?" Arto raised an eyebrow. "I wrote the book. If your changes are better than mine, I'll be the first to admit it. Publicly. In the next edition."
[Timeskip: Brought to you by chibi Rias and chibi Akeno reading books]
Rias sat cross-legged on the thick rug in Arto's study, the heavy leather-bound copy of Spellcrafting Formulas open across her lap like an ancient relic she was almost afraid to touch. The room smelled of old paper, cedar from the bookshelves, and the faint ozone hum that always lingered whenever Arto had been working with high-level mana constructs. He was downstairs in the Simulation Room now—running diagnostics or tweaking Sector 1 parameters—so the study felt strangely empty without his quiet presence.
Akeno lounged beside her on a floor cushion, one elbow propped on a low table, chin in hand. She had already marked her target: the cluster of formulas in Chapter 9 dealing with elemental manipulation and phase transitions. She'd circled three pages in soft pencil—places where the mana-to-element conversion leaked efficiency under high-entropy conditions, where the resonance constants felt slightly misaligned for this world's ambient mana density.
"I'm going for these," Akeno said, tapping the open book with her nail. "The lightning-to-fire pivot equation is solid, but the intermediate state bleed is wasting 7–9% mana every cycle. If I tighten the phase-lock rune here—" she traced a small arc in the margin "—and add a recursive damping term, I think I can push it to near-zero loss without increasing cast time."
Rias nodded absently, eyes fixed on the same pages—but not really seeing them. Akeno noticed. "You still haven't picked yours, have you?" Rias exhaled—slow, almost defeated. "I lied to him this afternoon," she admitted in a whisper. "I said I had three candidates. Intention-indexing, resonance collapse, emotional anchoring. But… I don't. I've read the book front to back three times. I've solved every problem set. I can cast every formula blindfolded. But every time I try to find a flaw… I can't. It feels perfect. Sacred. Like criticizing scripture."
She closed the book gently—fingers lingering on the worn spine. "He told me to question it. To challenge it. To break it if I have to. But how do I break something that's already saved my life a hundred times? How do I tell the man who wrote it—after thousands of years of blood and refinement—that I think it could be better… when I can't even see where?"
Akeno shifted closer—shoulder brushing Rias's. "Because he asked you to," she said simply. "Not because it's broken. Because it can be more. The Legion didn't survive by worshipping their old formulas. They survived by never being satisfied with them. That's what he wants from us. Not perfection in the past. Progress toward the future."
Rias looked at her—eyes shimmering with something between awe and frustration. "You make it sound so easy."
"It's not," Akeno admitted. "But it's honest. And he deserves honesty. Even if your improvement is small. Even if it's just one constant recalibrated for this world's leyline harmonics. It's still you saying, 'I see what you built… and I want to help carry it forward.'" Before Rias could answer, the study door opened quietly.
Robin stepped in first—notebook tucked under one arm, expression calm but attentive. Nami followed right behind, phone in hand, already mid-sentence. "—so the royalty waterfall for the premium sectors is locked at 12.7% net after tax, but I'm pushing for 14.2% on the black-ops sim tier because they'll pay it without blinking—"
Nami cut herself off when she saw Rias and Akeno on the rug, book open between them, expressions serious. She lowered the phone. "Teacher candidates," she said, voice dropping into mock-formal tones. "Progress report. What are you planning to dazzle our supreme author with tomorrow night?"
Rias flushed faintly. "I… haven't decided yet." Akeno lifted her chin. "I'm targeting the elemental phase-transition cluster. Leaks in the mana-to-element conversion under entropy stress. I think I can close the gap." Robin's smile warmed—genuine approval. "That's a good choice. Chapter 9 has been stable for centuries, but this world's ambient mana is… softer. More fluid. The old constants were tuned for Hell's density. A recalibration could shave real cost without sacrificing power."
Nami dropped onto a cushion across from them—legs crossed, grin returning. "And you, princess?" she asked Rias. "Still worshipping the book like it's the Bible of magic? Or are you finally going to commit blasphemy and improve it?"
Rias glared—half-hearted. "I'm trying. It's just… hard to find the flaws when everything works so well."
Robin settled onto the rug beside Rias, close enough that their shoulders brushed, her posture relaxed but attentive in that way only she could manage—present without crowding, observant without staring. She waited until Akeno had gone back to quietly annotating her own chosen section before speaking, voice pitched low and gentle, almost conspiratorial.
"You're facing what I call the 'generic good student' syndrome," Robin began, resting her chin lightly on her palm. "You're good—exceptionally good—at every part of it. Intention-indexing flows naturally for you. Resonance holds steady under pressure. Emotional anchoring… you've already internalized it so deeply that the formulas feel like extensions of your heartbeat. That's not a flaw, Rias. It's a gift. But it's also exactly why you're struggling to find 'the spot' to improve."
Rias looked down at the open page—fingers tracing the margin she had yet to mark. "I feel like… if I choose one thing, I'm ignoring everything else," she admitted quietly. "Like picking a favorite child. Everything works. Everything is elegant. How do I decide what needs fixing when nothing feels broken?"
Robin nodded—once, understanding. "That's the trap of being broadly excellent. You don't have a narrow specialty screaming for attention, so the whole field looks equally polished. But polish isn't perfection. It's just… high baseline." She glanced across at Akeno, who was now deeply absorbed in her lightning-phase equations, pencil moving with quiet confidence.
"Take Akeno. Her core is lightning. Elemental manipulation isn't just something she's good at—it's something her body and soul are tuned to. When she sees leaks in the mana-to-element conversion, she feels them like phantom pains. That's why she can spot cracks others miss. Her specialty chose her."
Robin's gaze returned to Rias—soft, patient. "Nami is the same. Numbers speak to her the way lightning speaks to Akeno. Mana consumption, efficiency curves, cost-per-cast metrics—those numbers sing to her. So when she looked at the book, the first thing she saw was waste. Not because the formulas were bad, but because waste is the one sin her mind refuses to tolerate. That's why she didn't stop at one improvement. She hunted inefficiency like prey and optimized the entire ecosystem."
Rias exhaled—slow, thoughtful. "So you're saying… I need to find what speaks to me. Not what I'm merely good at." Robin's smile warmed—just a fraction. "Exactly. You're not looking for the weakest link. You're looking for the part that keeps whispering to you, even when the rest of the book is quiet. The chapter that makes your fingers itch to write in the margins. The constant that feels slightly off, like a note that's almost—but not quite—in tune. The assumption that works… but could work more beautifully."
Robin leaned forward slightly "I've been watching you for a long time, Rias," she said quietly. "Ever since Sona hired me to spy on Arto—back when you were still the one person who spent the most time near him, day after day. You were there from the beginning, closer than anyone else. You've had the longest, deepest exposure to the core knowledge he uses. Not just the formulas, not just the applications… but the most basic factor of magic itself."
Rias tilted her head, brow furrowing faintly.
Robin continued, voice soft but certain. "Magic is the effect created by stable mana flows moving through a magic circle and bent by magic sigils. That's the definition you learned early—the one Arto gave you when he first started teaching. But the sigils… they're the building blocks. The alphabet. The atoms. Everything else—intention-indexing, resonance, phase transitions, emotional anchoring—is built on top of them. Change a sigil's angle by even a fraction of a degree, shift its curvature, alter its symmetry axis, and the entire downstream spell changes. Power. Stability. Efficiency. Side effects. All of it."
She paused—letting Rias feel the weight of the realization settling in.
"You excel at everything because you understand the sigils better than anyone else in this house. Not consciously, maybe—not in the way Nami sees numbers or Akeno feels lightning—but instinctively. You read them like breathing. You feel when they're misaligned before the math even shows it. That's why the book feels 'perfect' to you. You're already seeing the world through the same lens Arto used when he wrote it. You're not just good at magic. You're fluent in its native language."
Robin's smile was small, almost tender. "Even I don't have that level of instinctive mastery over sigils. I can analyze them, optimize them, reverse-engineer them… but you live them. That's your specialty, Rias. Not one chapter. Not one formula. The foundation everything else stands on."
Akeno looked up from her own notes—eyes wide with sudden understanding. "That's why you always catch the tiny inconsistencies before any of us," she murmured. "The little wobbles in the circle that no one else notices. You feel them in your bones."
Rias stared down at the open book—fingers tracing one of the oldest sigils in the margin, a simple three-stroke glyph for basic mana containment. "I never… thought of it that way," she whispered. "I just… knew when something felt off. I thought everyone could sense it."
Robin shook her head gently. "Not like you. Nami sees the cost. Akeno feels the element. I see the pattern. But you… you see the shape. The architecture underneath. That's why the book feels sacred to you—because you're reading it in its mother tongue. And that's exactly why you're the one who can improve it most meaningfully. Not by rewriting everything. By tuning the alphabet itself."
She leaned back—giving Rias space. "So stop looking for a single weak formula. Look at the sigils. Pick one family of them—containment, amplification, inversion, whatever calls to you—and ask yourself: Is this still the best possible shape for this world's mana? Could it bend the flow more cleanly? Could it leak less? Hold more? React faster? If the answer is 'maybe'… then that's your improvement. Even a 0.1% gain at the sigil level cascades into everything built on top of it."
Robin reached for a spare sheet of paper from the stack on the low table—nothing fancy, just plain white printer paper—and picked up one of Rias's pencils. Without a word, she began sketching in the center of the page.
A simple magic circle. Basic radial symmetry. Eight primary anchor points. A single intention-indexing rune at the twelve-o'clock position. A standard mana-flow loop threading through them like a heartbeat.
Nothing elaborate. Something a first-year student at the Underworld academy might draw on their first day. She set the pencil down and slid the paper toward Rias. "Now tell me, dear," Robin said, voice soft but carrying that unmistakable undercurrent of challenge, "what happens if I tweak this rune?"
She tapped the intention-indexing glyph at the top—specifically, the third spiral arm of the sigil. "I won't cast it yet. I won't even open the simulation analyzer. I want to hear your take first. Pure instinct. Pure reasoning. Go." Rias stared at the circle. Her first impulse was deference—the old reflex that still whispered this is Arto's work, it's already perfect—but she caught it, breathed through it, and leaned closer.
She traced the rune with her fingertip—once, twice—feeling the shape in her mind more than seeing it. "If you extend this third spiral arm by even a quarter-turn," she said slowly, "you're not just increasing the rune's surface area for mana intake. You're shifting the harmonic node. The intention lattice will resonate at a slightly lower frequency… which means the mana-flow loop will experience micro-oscillations at the cardinal anchors. Those oscillations will propagate outward in a damped wave, but because the circle is radially symmetric, the damping won't be uniform. The eight o'clock and four o'clock anchors will see constructive interference. The result—"
She paused—eyes narrowing as the mental simulation finished running. "—a 4–6% increase in peak mana throughput at the cost of 11–13% higher instability during the first 0.3 seconds of casting. Fine for sustained effects like barriers or enchantments. Dangerous for anything explosive or instantaneous. The circle might hold… or it might fracture along the interference lines and backfire."
Robin didn't speak. She simply lifted her hand—palm open—and let a tiny spark of mana flow through the sketched circle on the paper. The lines glowed soft violet for half a second. Then the simulation overlay appeared above the page—ghostly holographic lines tracing the mana flow in real time. Numbers flickered beside each anchor point. Waveforms danced.
Rias's prediction had been exact—down to the decimal place on the instability spike. Robin let the hologram fade. She turned to Rias—eyes bright with quiet, genuine pride. "A few milliseconds slower," she said softly, "and I could still do it. But not as fast as you just did. Not as instinctively. Not with that same… clarity."
Rias stared at the now-dim paper—then at Robin. "You're the Spy Queen," she whispered. "You process intel from every corner of the globe in real time. You read patterns no one else sees. How can I possibly—"
Robin shook her head—cutting the self-doubt off before it could finish. "Because this isn't about raw processing speed. It's about pattern intuition at the foundational level. You don't just see the circle. You feel the mana inside it. You sense the tension in each spiral arm the way a musician hears a string slightly out of tune before anyone else notices. That's not something you learn. That's something you're born with… and then hone until it sings."
She leaned back slightly—giving Rias room to breathe. "I can read a thousand data streams at once and find the anomaly in under a second. But you just looked at a single rune and predicted the exact failure mode of an entire casting sequence—without even closing your eyes. That's not just talent, Rias. That's mastery of the core language of magic itself. The sigils. The bones of every spell ever cast."
Akeno—quiet until now—set her pencil down and looked at Rias with something close to awe. "You really are the best of us at this," she said softly. "We all knew it. You just never let yourself believe it." Rias's throat worked—once, hard.
Robin reached over—covered Rias's hand where it rested on the book. "You don't need to find 'a flaw' tomorrow night," she said. "You need to find your improvement. The one only you can see. The one only you can feel. Trust that instinct. It's never steered you wrong."
Rias looked down at the book again—not as scripture this time. As a conversation waiting to be continued. She exhaled—slow, steady—and opened it to the foundational sigil chapter. "I think… I know where to start."