A knock hit his door but Cassian didn't look up.

"If that is you, Fred, tell George I am not giving extra credit for 'combat baking.'"

The door creaked open anyway.

Bathsheda stuck her head in. "Combat baking?"

"Don't ask," he muttered. "How is the rune-mangling going?"

She stepped in, closing the door behind her with her boot. There were fresh streaks of ink up one sleeve, smudged in a way that suggested she wiped her quill there more than once without realising as she always did.

She crossed the room and sat on his lap like that was where she was headed all morning. He didn't say anything, just looped one arm around her waist and let his hand rest against her lap.

"It was fine," she muttered, making herself comfortable, like he was furniture. "Sixth and seventh years are still manageable. The ones who passed their OWLs actually want to be there, so at least they shut up and listen. Third-years though, they are a problem. Too much optimism. Think if they carve a single rune right, they will cause an explosion." She shifted, drawing his other hand to her thigh without really thinking about it. "Fourth-years forgot everything over the summer. Whole term reset. Like someone Obliviated them in June."

"Ah yes," Cassian murmured, "the sacred cycle of academic regression. They cram, they pass, they promptly flush it like spoiled potion. Happens every bloody year."

"They are unbearable," she said, leaning her cheek against his shoulder.

"You are describing teenagers."

She just snorted in resposne.

He ran his fingers along the ink on her sleeve, pausing at one smear near her elbow. "What did you throw at them?"

"Runic function breakdown. Simple chain spells. Conditional logic. Barely anything. Half of them still drew everything backwards."

"You didn't hex anyone?"

"Tempted."

Cassian kissed the crown of her head. "You've gone soft."

She snorted. "You are one to talk."

He huffed a laugh.

They sat like that for a bit. Her thumb brushed the inside of his wrist. His hand rested warm against her hip. Somewhere in the castle, a bell rang. He didn't care which one.

She tilted her head, speaking against his jaw. "You are getting a reputation."

"Always do. What is it this time? Revolutionary? Rogue educator? Wand smuggler?"

She looked up at him with a grin, eyes a little too smug for someone claiming exhaustion. "The young, dashing professor who swooped the helpless Rune expert off her feet."

Cassian scoffed. "Helpless? You stabbed a sixth-year's essay with your wand quill year."

"He drew an 'Y' instead of 'ᛉ'. That is a death rune." She nudged his chest with a knuckle. "Which, ironically, I considered using."

"Might've improved his grammar," he muttered, mostly to himself.

"The Slytherin girls are obsessed. Half of them are convinced you used a love potion." She said with a laugh.

Cassian chuckled. "Brilliant. Was wondering when that rumour would start. Thought I would at least earn it with a dramatic hallway kiss or something."

"You do walk like you got a dramatic song playing every time you enter a room."

"I do," he said, "it is called exhaustion in E minor."

She laughed against his shoulder.

"How are the darlings of fourth-year runes?" he asked.

"Collectively? Useless. One of them tried to translate an Icelandic binding glyph with a textbook from Beauxbatons. Half the class copied him."

"Oh good," he said. "Cultural misunderstanding and academic laziness. Our two core values."

"They think runes are a puzzle game. Plug in a few symbols, and poof, enchanted tea set."

He shrugged. "A rather genius Muggle calls it Natural Selection."

Bathsheda blinked at him like he just started speaking Gobbledegook again.

Cassian sighed and leaned his head back against the chair with a quiet thunk. "Right. Add Darwin to the list. Along with rockets, jet engines, microwaves, and basic risk assessment."

She squinted. "Natural... what?"

"Selection," he repeated. "The scientific concept, not a game show. Muggles figured out survival favours the ones who adapt. Change. Learn or you die, and those who adjusted carry on."

She snorted softly. "We have that in magic too. It is called 'don't stand in front of a basilisk.'"

"No, that is called instinct or reason. Or running for your life," he said. "Muggles built entire systems around this. Genetics, evolution, breeding charts. Though some of them also thought cucumbers cured depression, so swings and roundabouts."

Bathsheda gave him a long look. "How do you know all this?"

"I read books. Big, terrifying ones with no moving pictures." He shook his head with a laugh. 'Also, I lived a whole other life, but that is a longer story.' He added in his mind, before sighing, "In short, your rune kids failing their logic exams is just Darwin in action."

She looked mildly horrified. "You are saying I should let them fail?"

"I am saying they are choosing extinction with every reversed binding rune. Who am I to interfere with the natural order?"

She dropped her forehead against his collarbone. "You are the worst."

"Statistically improbable," he muttered into her hair. "I am at least in the top twenty percent."

“So, tell me,” she said after a beat of silence.

"About?"

"Your second-years. You looked smug when I came in."

He rolled his eyes, rant brewing within him as if was waiting for anyone with ears to ask. "The way magicks think is limited. Rigid, boxed in. You got to swish the wand just so, pronounce the syllables like a bleeding opera singer, and cast the spell exactly the way the first bloke did it a thousand years ago. God forbid you get creative. Break the mould and suddenly you are reckless. Irresponsible. Possibly dark. This sort of generational cloning? It kills imagination. Nature trims the fat. Stop using a part long enough, and it withers. I think magicks have finally evolved into losing their bloody imagination."

Bathsheda murmured something unintelligible against his shoulder. "You sound personally betrayed."

"I am," Cassian muttered. "I drew an imaginative age line around a cup and asked them to put their names in. Their first idea? Polyjuice or ageing potion."

She scoffed. "They are solid choices. I would probably use runes, but..." she waved a hand at herself, "...occupational hazard."

He rubbed the bridge of his nose, "How about just throwing a bloody paper over the line? You know, the kind of thinking that doesn't involve stealing someone's toenails or waiting a month to digest shame?"

She blinked. Took a second to answer.

It sounded silly, but she was caught off guard. Not by the idea, exactly, more by how simple it was. Obvious, even. Toss a slip of paper across a line instead of crawling through magical red tape? Ridiculous. And completely valid.

The problem wasn't the idea itself. It was the instinct. Every kid in that classroom had been taught, formally or not, that if something couldn't be solved with magic, it had to be ancient, cursed, or written by Merlin's personal assistant in blood and dragonbone ink. Anything else was a trick.

Bathsheda looked faintly scandalised.

"So, you are saying the answer to a magical challenge was not magic."

"Oh no. I am saying the answer was gravity. That terrifying Muggle concept. Dropping things. Wild, I know."

He sighed. It wasn't that they were stupid.

Just... trained. Indoctrinated, really. The same way he would flinch at a dragon instead of trying to cast a shield, or, hypothetically, Apparate away, if he could, because somewhere deep in the spine, that is what the body thought survival looked like. Pure reflex.

Brains were muscles. Neglect them, they shrivel. Magicks, far as he seen, hed spent centuries lifting the same five mental weights. Spell, counter-spell, charm, rinse, repeat. Any idea that didn't start with a wand and end in Latin got tossed in the bin.

He didn't blame them. Hogwarts, the Ministry, even bloody bedtime stories, they all ran on a script. One way to win. One answer to the riddle. And if you tried anything else? You were reckless. Dangerous. Or worse, a Muggle-born.

Bathsheda didn't say anything at first. Just blinked slowly like someone trying to process the idea of butter that didn't come from a charmed churn. Cassian watched the mental cogs churn behind her eyes, faintly amused.

"You are saying," she said eventually, "they failed, because they were trained to fail?"

"Not trained to fail," Cassian said. "But yes. No one tells them to think sideways. They are told what wand movement to use, how many flicks, and when to say the incantation. You try anything else, they act like you've slapped the Founders."

She frowned. "It is not that rigid."

"Name one Hogwarts subject that encourages rule-breaking."

A pause.

"…Divination?" she tried.

"Please. That is not a class, it is a lottery."

She snorted a laugh, leaning into him more. "So what, you are going to retrain their instincts? Teach them all to throw things at wards instead of using their wands?"

"I am not trying to turn them into Magical guerrillas." He shook his head slightly, "I just want them to stop treating spells like bloody vending machines. Tap the button, get the effect."

Bathsheda tapped his wrist idly. "You know this won't win you points with the parents."

"Good," he said. "They are the ones who need deprogramming first."

She didn't argue. Just let out a long breath and went quiet.

It struck her again, how different Cassian was. Not just the dry jokes or the way he taught like he was holding court in a pub rather than a classroom, but at the root of him. If he wasn't a Rosier, and if she didn't know him from school, she would have put money on him being Muggle-born. Maybe not even a bet. Just a fact. One of those quirks you spotted after the fifth time he asked a question that didn't belong in their world.

Even back in that cave, when the ceiling had started to give, her wand had been in her hand before she blinked. Instinct. Protego. Classic. His hadn't even left his coat. He just grabbed her arm and yanked her sideways, like instinct didn't start at spellwork but at "move or die." It made her feel stupid, later. All that training, all those drills, and the man next to her moved faster without even drawing.

He thought in straight lines. Sometimes brutally so.

And it wasn't just caves.

She was often baffled how Cassian could navigate Muggle infrastructure like he built it. Just moved through the mess like he was born with a street map stitched behind his eyes. There was also travelling. She used Muggle trains in Norway with him. Straight through the barriers, picked the right platform like it was second nature. Tube map lit behind glass, half the colours rubbed off, and he barely glanced at it.

She was shocked to see how evolved muggle transportation was. Last time she boarded one, it was all steam and creaking metal, every carriage rattling like it might come undone if someone sneezed too hard. Like Hogwarts Express, but worse. Now? Now they went underground. Underground!

She read about tubes before, but when they stepped into one, she stood still for a full ten seconds trying to understand how the bloody ceiling wasn't caving in. It didn't help that the train shot forward like it was being chased. No horses. No steam. Just noise and a blur of light and something that felt very much like being kidnapped by a steel coffin on wheels. She gripped the overhead bar the whole time, silently reciting every defensive rune she knew. He just sat, legs stretched, reading a book as if the screeching metal tube wasn't dragging them through the belly of the Earth.

She made it two stops before she bolted out like a spooked Kneazle.

Cassian, of course, had loved every second. He had laughed for ten solid minutes.

"Didn't even make it to Berg," he wheezed. "Brilliant. I am putting that on your grave."

"Shut up," she snapped, dragging herself away from the edge of the platform. "You can't tell me that wasn't cursed."

"Nothing is cursed, you just don't trust anything that moves without a wand."

"Of course I bloody don't. That thing didn't even puff."

He grinned, utterly smug. "That is called engineering."

Bathsheda glared, pulling her bag up like it might shield her from further nonsense. "You are a Rosier. You shouldn't even know that word."

There were little slips like that all the time. Moments where he referenced things she didn't understand, offhand mentions of nuclear power, of 'satellites' and 'the internet' like they were old family friends. He didn't flaunt it, just said them like everyone knew what they were.

And now, curled on his lap in his room that smelled faintly of ink and whatever coffee he was hoarding, she could feel it again. Like his brain was wired a bit differently… built somewhere else.

----------------------------------------

Spoiler

[collapse]

Tell me... when you look in the mirror,

do you pretend you dropped a Rate…

or just avoid mirrors entirely?