TheFanficGOD
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CASS156- No
🕑 Added 2025-10-15 18:28:19 +0000 UTCOn Friday, Cassian was cornered halfway through his walk to his class, tea in hand and no intention whatsoever of doing anything noble with his afternoon.
"Professor Rosier, a word please," Pomona said, smiling far too sweetly for his liking.
Cassian raised a finger without slowing. "Nope."
Both women stopped.
"No to what?" McGonagall asked, one brow already twitching.
He waved vaguely at them. "Whatever this is. No to all of it. Joint efforts like this never end well for me."
Pomona looked amused. "We were only going to ask if—"
"Professor Lupin is feeling unwell," McGonagall cut in. "We were going to ask if you could substitute for him."
Cassian stopped walking. "Oh. Haha, sorry, sorry. Thought you were trying to flog me a fundraising scheme or another Bake for Badgers weekend." He scratched the back of his head. "You should've opened with that."
Pomona smiled. "You didn't exactly let us."
"True," Cassian admitted. "My bad."
McGonagall squinted at him. "So?"
He dropped the smile. "Still no."
And walked off before either of them could respond, ignoring whatever curse McGonagall muttered into her scarf.
***
The classroom door creaked open.
Cassian stepped in, raking a hand through his hair. "Alright, lovely headaches. Let's make a pact, if you behave, I won't assign too much essay, and if I behave, I won't explode"
Ginny Weasley was up front, already sitting in her usual place. Colin Creevey waved at him the moment he looked up.
Cassian waved back, setting his tea down on the desk with a quiet clink. "Right then. Who here knows what a General Counter-Spell is?"
Every hand shot up, bar one Ravenclaw who was halfway through peeling the corner of her parchment.
"Brilliant. That means you've all got access to one of the most useful bits of magic in your arsenal." He uncapped the chalk and scratched Finite Incantatem across the board in quick, slanted letters. "And no, I'm not exaggerating. Not even slightly."
He turned back to face them, arms crossed. "Why d'you reckon I'm calling this an amazing weapon?"
Colin's hand went straight up like he was gunning for a medal.
Cassian pointed without looking. "Creevey."
"It stops spells?"
"More or less. But lots of spells stop other spells. What makes this one stand out?"
A pause. Colin's hand hovered, unsure if he should take another shot.
Ginny raised hers. He nodded at her.
"It's broad," she said. "It works on loads of things at once. Not just one spell."
Cassian clicked his tongue. "Close. Very close. It's not that it works on everything. It's that it doesn't care what it's cancelling. It just... wipes the slate. You ever clean a blackboard with your wand? This is that. But for reality."
A few giggles. Luna tilted her head and murmured something about cosmic chalk.
"Right," Cassian continued, striding along the front row, "You're in a duel. Someone jinxes your wand arm. Your leg's stuck. There's ink in your eyes. What's the first thing you shout?"
"Finite Incantatem," came the answer, scattered and eager.
"Exactly. Quick reset. One go-to command that levels the field again. Doesn't fix everything, can't undo a curse if the wand core's melted and your hair's on fire, but it gives you a fighting chance."
He stopped near the windows, leaned a shoulder against the frame. "Thing is, half of you will forget this exists the moment someone hexes your shoes off. You'll panic. You'll flail. You'll scream something ridiculous like Expelliarmus! at a broken ankle."
Someone snorted. Luna raised a hand. "What happens if you try to Expelliarmus a broken ankle?"
Cassian considered it. "Probably the shoe flies off and hits you in the face."
"Noted," she said, scribbling that down.
"Now," Cassian clapped, eyes flicking across the classroom, "the history of this spell is as good as the spell itself. And no, I'm still not exaggerating."
He gave a little shiver. "Forgive me. I don't usually get to teach magic with Mesoamerican roots. Bit of a treat."
"This spell's older than this castle. Older than wands. Came from a culture that carved magic into stone before the rest of Europe figured out how not to die from damp socks."
Colin raised a hand.
Cassian didn't stop to explain what an exaggeration was. "The Nahua, what your textbooks occasionally lump under 'Aztec,' they had a word for it, Nemitstlaçotla, roughly meaning 'I release you' or, less romantically, 'I undo this tie.' Originally used to sever magical bindings. Curses. Hexes. Or, in one very dramatic account, someone's marriage."
As the class laughed, Cassian strolled between the desks, one hand tucked into his robe pocket, the other flicking chalk dust off his sleeve.
"Mesoamericans were absolute menaces with curses," he said, stepping neatly over a sprawled school bag without looking down. "And by extension, counter-curses. I say by extension, because—"
He turned to face the room.
"It's a rule of thumb in magical history. Things get invented when?"
The class answered in a ragged chorus, "Needed!"
Cassian pressed his hand to his chest, mock-sniffling. "I'm proud of all of you. Touching, really. Yes, needed."
He spun on his heel and scrawled a rough diagram on the board, an etched altar, stylised glyphs. "Imagine this, you're in a society where curses are used to punish thieves, bind contracts, or, if someone's feeling extra creative, curse the maize harvest of the bloke who stole your goat. You need a way to undo that."
Luna raised her hand. "What happened to the goat?"
He grinned. "Ascended to heaven and became the lord of the goats. Shared his blessings widely on the way up, benefitting many."
Luna's eyes sparkled.
He tapped the glyph for nemitstlaçotla, underlining it. "These people didn't just shout counter-spells and hope for the best. They carved them. Ritualised them. Put effort into scrubbing the magic out."
"Now," Cassian said, tapping the board with his wand, "when this counter-curse first turned up, it changed everything. One incantation, and boom, gone. All the leftover bits from whatever curse you'd been hit with? Gone. Side effects? Gone. Sticky magical residue making your teeth hum? Wiped. It was a bloody miracle."
He tossed the chalk into its tray, brushing dust from his fingers. "We don't know who invented it. Records from the Nahua get a bit patchy around that period, Spanish weren't exactly known for their diligent archiving. Or cultural sensitivity."
A few of the students grimaced. Cassian gave them a lazy shrug.
"Still, whoever figured this one out probably saved more people than any wand-waving war hero we put on cards. One phrase carved into a stone altar, and suddenly the village shaman wasn't getting mobbed by villagers who'd grown third ears or permanently smelled of fermented cactus."
Cassian leaned back against the desk, arms loosely crossed. "Thing is, you lot use this spell like a reset button. Fair enough, it mostly is. But originally? This was a last resort. You said those words, it meant you were cutting the cord. Severing magic already rooted deep in your system. Bit risky if the spell holding you together was also the thing you were trying to remove."
A few Ravenclaws had paused their quills. Ginny was still scribbling furiously.
He shook his head. "I rarely say this, but turning that spell into something Latin and wand-friendly was bloody genius. So, props to Madam Althea Roswick. Seventeenth-century scholar, bit of a menace, brilliant at hex theory. Died after a duel with a disgruntled cousin. Whole mess over a cursed rocking chair."
A few Ravenclaws perked up. Cassian waved a hand.
"Yes, the chair survived. No, it's not in the school. Stop thinking about stealing it."
"Roswick reworked the phrasing, took the Nahuatl structure and made it wand-compatible without gutting the intent. Which, by the way, is harder than it sounds."
He scrawled her name across the board, under the glyph. Althea Roswick. "You want to talk magical evolution? This was the point spells stopped needing bone dust and blood and started needing just breath and will."
He turned back to them. "Well. Breath, will, and not being a complete muppet."
Luna raised her hand. "Did she name it?"
"Nope. The Latin was slapped on later by some French academic who thought Nahuatl looked messy on a syllabus."
Luna tilted her head. "Seems rude."
"Welcome to magical academia," Cassian said. "If it's not in Latin, half the scholars won't read it. Other half will try to hex you for spelling it differently."
He tossed the chalk onto the desk and leaned back against it. "Point is, this one spell has been polished, pushed, renamed, and recycled for hundreds of years. And you lot get to use it in a duel like it's just another line in the syllabus."
He looked at the ceiling for a moment, sighed. "Honestly. I envy you."
A few of them blinked.
Colin raised his hand. "Why?"
"Because if someone handed me a spell like this when I was your age, I'd have made far fewer hospital visits. And probably still have the full use of my left eyebrow."
Class booed.
"You're not that old, liar!"
Cassian made a face. "I am old. In soul. And in knee. Get out. One foot on how brilliant Finite Incantatem is, one foot on how amazing the person who created it must've been, and one foot to thank Althea Roswick profusely. Yes, three feet. Figure it out."
Someone muttered something about magical mutations. Another asked if having three feet improved spellwork.
Colin waved again.
"Creevey," Cassian said. "Don't bring a camera next lesson. The last spell I'm teaching has backfire potential and I don't want photographic evidence of student incineration."
"Yes, Professor!"
The door closed behind the last straggler, leaving Cassian alone with half a blackboard of scrawl, a nearly empty tea mug, and a trace of chalk in his cuff.
He stared at the Nahuatl glyph for a moment longer. Strange thing, really, how the world changed around an idea that old. People got on with their lives, cast the same spells in different tongues, and forgot where it started. Just another incantation now. Latin, polished, wand-flourished. But it had come from somewhere that bled magic through stone.
He wiped the board clean with a flick of his wand.
Comments
TheFanficGOD
Probably doesn't work same way. Snape was fine after substituting for Lupin 🤔
JamPoe81
Were Pomona and McGonagall trying to kill Cassian? Were they hoping he dropped dead the second his substitution for Lupin ended?
Maniac000
That would be funny.
SwiftFate
Cassian should teach the history of Revelio, so he can go around being a menace chanting "Revelio!" Every 10 feet like a Hogwarts Legacy character discovering all the castle secrets lmao, it would drive everyone crazy. As a side note, surprised you haven't made some of that stuff more canon as it expands Hogwarts immensely and has a lot of historic potential. Especially for Hogwarts but in the general surroundings too. Take the catacombs for example, or some of the ancient challenges hidden away. More than just the chamber of secrets or room of requirement after all.
