The classroom door opened with a creak dramatic enough to make the hum of conversations dissolve into the air like smoke before a gust of wind.
In walked Professor Shizuka Kamizuki, the math teacher and a high school veteran with the patience of a bodhisattva and the gaze of a sharpshooter. She was in her early thirties, with brown hair tied in a tight bun, thin glasses on her face, and a posture so upright it betrayed both years of teaching and zero tolerance for nonsense.
"Good morning, class. Open your books to page 112. Today, we'll review exponential functions before Friday's test…"
The mere mention of the word "test" drew collective sighs and synchronized eye-rolls. A school orchestra of contained despair. Kazuya, in the back row, didn't budge. He kept his chin propped on his hand, staring out the window as if expecting a dragon or a Servant to appear on the soccer field.
"Exponential functions, huh?" he thought. "At least it's more interesting than classical literature… slightly."
Professor Shizuka began writing on the whiteboard with a black marker. Her handwriting was perfect, clear, legible—rare in the world of teachers. Meanwhile, the students settled into their seats, some trying to look interested, others just surviving.
Kazuya finally stirred. He grabbed his book with lazy slowness and opened it to the indicated page. Not because he was motivated, but because he knew Professor Shizuka had enviable aim with chalk and no hesitation in using it as a motivational projectile; he recalled through his predecessor's memories that she'd nailed a classmate who fell asleep earlier that week, on his first day at this school.
After a few minutes, Professor Shizuka paused her writing, the black marker still in hand, and turned to face the class with that dangerous glint in her eyes.
The kind of look teachers develop after years on the battlefield… I mean, in the classroom.
"Since last week we had some… unforeseen circumstances, today we'll rectify that."
She twirled the marker between her fingers, and then her gaze landed on him. Back row. Corner of the room.
"Ryougi-san…" she said, her voice clear, firm as the Pythagorean theorem. "Come to the board…"
The class turned their necks in unison. It was like watching a row of dominoes fall.
Kazuya let out a sigh, as if he'd been called to save the world again.
"Sure…" he said, tucking the bookmark into his book as if it were a necessary drama.
He walked down the aisle with calm steps, his aura slightly lazy but steady, and took the marker from the professor's hand as if accepting a scepter. The class whispered. Some glanced sideways with anticipation, others with pity. He was new, after all; they didn't know what to expect. Despite his looks, no one knew if he was smart.
"I want you to solve the equation 2^x = 16 and then explain the application of exponential functions in population growth…" said the professor, crossing her arms.
Kazuya raised an eyebrow.
"That's it?" he asked.
Muffled laughs echoed, but the professor didn't smile.
He then wrote on the board with absurdly clean handwriting:
2^x = 16
x = 4
He turned to the class.
"The value of x is 4 because 2 to the fourth power is 16. Easy. As for the application…"
And then, as if flipping a switch, Kazuya began explaining. He talked about how populations—people, bacteria, or even mutant demonic cells in a lab, if they wanted to make the class interesting—could grow exponentially in favorable conditions. He used real-world examples, modern economies, and even cited an article he "read by chance."
When he finished, there was an almost respectful silence in the room. Rias watched him with a curious smile. Sona crossed her legs slowly, narrowing her eyes as if observing an intriguing equation. And Akeno… well, Akeno seemed to be enjoying herself more than she should.
"Well done, Ryougi-san…" said the professor, adjusting her glasses, though they didn't need adjusting. "You may return to your seat…"
Kazuya nodded, handed back the marker, and walked back to his chair under mixed gazes of surprise and renewed interest. He sat and stared at the ceiling.
"Congrats, Kazuya. Now you're officially the 'mysterious and smart transfer student' of the class. Next step: getting recruited by a demonic faction or a goddess with emotional issues."
Time passed as it should—that is, slowly. The math class ended with the usual flood of homework, and Professor Shizuka left like a general who'd won another campaign. When the bell rang, the students exhaled a collective sigh of relief, as if they'd survived crossing the Sahara.
But the relief was short-lived. Ten minutes of break…
Because, of course, school life is an eternal cycle of hope and frustration. The next class was…
"Good morning, everyone…" said a new voice, soft yet firm.
The class turned to see the Classical Literature teacher, Mizuno-sensei, enter. She was younger than Shizuka, with dark hair loose to her shoulders and a presence that was half ethereal, half "I'll assign five chapters of *The Tale of Genji* for you to read by Friday." She carried a stack of papers and a lightness that fooled no one.
"Today, we'll start a paired project…" she said, setting the papers on the desk. "The proposal is simple: analyze the symbolism in Japanese and European classics. I'll draw the pairs. No complaints."
A murmur of tension rippled through the room. It was that moment when fate decided who you'd hate or love for the next seven days.
Kazuya, of course, just propped his chin on his hand again. He'd accepted that the universe was rarely random with him. And, as if the world wanted to confirm this…
"Ryougi Kazuya…" Mizuno-sensei announced, glancing at the sheet, "…will be paired with Rias Gremory…"
The entire room let out that dramatic "oooh" you only hear in teen movies.
Rias raised an eyebrow, but a smile curved her lips.
"Looks like we're fated to work together, Kazuya-kun…" she said, turning in her chair and looking his way.
Kazuya blinked, a bit surprised, but responded with a faint smile.
"Well, seems like it…"
Something's fishy here; it feels like they're pushing him toward the demons…
As Mizuno-sensei explained the project details—something about comparisons between *The Tale of Genji* and *The Sorrows of Young Werther*—Kazuya glanced out the window again.
With each topic, the students' gazes grew emptier. Some stared into the void as if witnessing the birth of a black hole. Others had already given up on life.
"Ryougi-san and Gremory-san…" Mizuno said finally, "you'll take theme four: 'The duality between appearance and essence in male figures of classic novels. From Genji to Werther, what lies behind the charm?'"
A few laughs escaped. Kazuya just raised an eyebrow again. It was clear. His luck was always meticulously scripted.
The professor ignored the comments and went on explaining the final instructions for the project. Groups, deadlines, format… It all became white noise for many, but Kazuya, used to absorbing information with near-magical efficiency, mentally logged everything. At the end of the class, Mizuno-sensei gathered her papers and said:
"Good work, everyone, and remember: read the texts before pretending you understood them."
The bell rang shortly after. As if the sound unleashed a dispersion spell, students stretched, yawned, sighed. Another ten-minute break.
But before Kazuya could even lean toward the window again…
"Hey, Kazuya-kun," said Rias, approaching with rehearsed elegance. It was the kind of presence that made every eye in the room turn automatically. Boys frowned. Girls wrinkled their noses. The world grew slightly tenser.
"Gremory-san," he replied, turning slowly, as if her appearance was expected.
"About the project… I thought it'd be more practical to do it somewhere quiet. Like your place, maybe?"
A second of silence. Then a muffled chorus of reactions: "At his place?" "She invited herself?" "Is that allowed?"
Kazuya kept his serene expression.
"Works for me. This afternoon, five o'clock, good?"
"Perfect," she said with a smile that could almost be called victorious.
But before she could say more, another familiar voice cut in:
"My, my… Such efficiency, Rias. Already scheduling scholarly visits to male residences?" said Akeno, appearing beside them with a mischievous glint and a smile sweet enough to unnerve a monk.
Rias blushed, a faint pink tinging her cheeks.
"It's a project, Akeno…"
"Of course, of course… A project. I get it. Just curious if the theme is Werther or… literary seduction," she whispered, chuckling softly.
Kazuya raised a hand, as if offering peace:
"If you're worried about missing something interesting, you can come along. We've got tea. And a couch."
Akeno blinked, surprised for a moment, then smiled even wider.
"What a gentleman. Careful, Rias… he's inviting me too. Are you good at sharing?"
Rias blushed harder.
"Akeno!"
The romantic tension—or whatever that force field between Rias and Akeno was—was cut short by the abrupt entrance of the new Chemistry teacher, a lanky man in a white lab coat, hair slicked back with so much gel it could double as thermal insulation, and a mustache that seemed to have its own personality.
"Good morning, my young alchemists of modernity!" he announced with exaggerated enthusiasm. "I'm Professor Minobe, and today we'll talk about covalent bonds… which, honestly, are more reliable than many human relationships."
The class didn't know whether to laugh or worry.
The professor launched into his lesson with theatrical flair, using plastic spheres to simulate atoms. At one point, he shouted, "BEHOLD THE REACTION!" as if narrating an epic battle.
It was educational.
At the very least, memorable.
Rias spent half the class taking notes with aristocratic efficiency, and the other half sneaking glances at Kazuya, who pretended not to notice, though it was impossible not to feel the noble redhead's radar locked on him.
Akeno, on the other hand, was clearly having fun with everything, doodling something that looked like a heart in the corner of her page. Or maybe a diagram for mass destruction. Hard to tell with her.
Meanwhile, Sona and Tsubaki remained silent, focused on the lesson.
The class ended with a warning that there'd be a practical experiment next week, prompting half the class to pray no one blew anything up.
When the bell rang, the room became a sea of backpacks being hoisted and chairs scraped. It was the sacred hour of the lunch escape. While most students rushed to the cafeteria as if their survival depended on a plate of kare, Kazuya took another path.
He climbed the stairs with calm steps, weaving through the student flow. Opening the door to the rooftop, he was greeted by a gust of fresh air and the distant sound of birds that, unlike humans, didn't care about tests, hormones, or mustachioed professors.
The rooftop was empty, as always. His place of peace. Silence, blue sky, and a panoramic view of Kuoh City. He sat against the railing, pulling his lunch from his bag—something his predecessor had prepared and left in the bag the day before.
For a few minutes, he was just a normal kid.
The peace ended, like all good things, with the bell.
The next class was English, taught by Yamamoto-sensei, a woman with an evident fascination for British culture. She entered the room wearing a scarf with a Union Jack print and started the class with a "Good afternoon, class!" that sounded almost convincing.
Kazuya responded with a drawled "Good afternoon" and braced for another fifty minutes of irregular verbs, idiomatic expressions, and pronunciations that would make Shakespeare roll in his grave.
Rias, of course, excelled in the subject. She spoke multiple languages. Akeno… well, she seemed more interested in turning simple sentences into something suggestive. When the teacher asked for an example of "Can you…?", Akeno replied with:
"Can you handle the truth… or me?"
The room erupted in laughter, and Yamamoto-sensei blushed before pretending she hadn't heard.
The final class of the day was led by Tanaka-sensei, an old man as tough as bamboo in winter. He didn't speak—he declared historical facts as if he'd lived through every battle.
"And then, Oda Nobunaga…" he said, as if about to summon the war demon himself in the middle of the room.
Kazuya paid attention. History calmed him. It also helped him understand how Japan dealt with power, honor, and betrayal. Familiar concepts, even if wrapped in a different guise in this world.
Rias took methodical notes. Akeno… was doodling again. A map of the Battle of Sekigahara or a caricature of the professor? Impossible to say.
When the class ended, the professor simply said, "Read chapters 5 through 8. And remember… those who don't know the past repeat its mistakes."
Kazuya muttered to himself, "Or become the protagonist of an isekai, which is sometimes worse."
The final bell rang. Backpacks were hoisted, desks scraped, sighs released. The school had completed its ritual cycle of learning and mild mental torture.
Kazuya left at a leisurely pace, his uniform pristine, his expression calm. Outside, the sun still gilded the city's buildings. Kuoh seemed so peaceful it was hard to believe the three major supernatural factions in the world had their eyes on it.
He let out a sigh, stuffed his hands in his pockets, and walked along the sidewalk.
"Time to prep the house… After all, I've apparently got a demoness coming over to study *The Tale of Genji* with me."