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SD: CH167 - The Geometry Of Desire
🕑 Added 2025-05-23 17:25:05 +0000 UTCCho had never imagined that the thrill of Ancient Runes could feel like an affair.
Not metaphorically—no heart-fluttering academic crush. This was something far more visceral, more dangerous. A sharp-edged secret with the power to unravel everything she’d so carefully curated: her reputation, her loyalties, even her self-image.
It had all begun after that absurd moment in the library. When Potter, with unnerving calm, had claimed he was going to rig the Triwizard Tournament.
She hadn’t believed him—not truly. But the way he had said it, casual and precise, like someone already walking ahead of the game… it lingered.
So, she had gone to Professor Babbling.
It was the perfect excuse. Cho had always performed near the top of her class in Ancient Runes, ever since third year. But she’d never ventured beyond theory into the deeper mechanics of application.
Until now.
“I was hoping to ask about the Perthro–Algiz Interference Matrix,” Cho said when she arrived at the professor’s office. “I… recently spoke with Potter about it.”
Professor Babbling’s eyes gleamed with immediate interest. “The Perthro–Algiz Interference Matrix? So that’s what he’s been so secretive about.”
Cho hesitated—only slightly—before smiling politely. “I’m not sure I’d call it secretive, Professor. He was quite open about it.”
Something she still hadn’t digested. But that was another matter.
“The fourth-years were assigned papers on rune history and interpretation,” Babbling mused aloud. “Just as I assigned your year’s essays on three-dimensional matrices. Mr. Potter told me he was interested in Perthro—which was unconventional enough. But I assumed he was exploring it historically, not…” Her eyes narrowed with academic curiosity. “…something this specialized.”
Cho paused. Then said clearly, “He’s working on an application of Vane’s Second Principle—exploring what happens when a Fate variable is inserted into a ritual to enforce a predetermined outcome, regardless of environmental variables.”
Babbling froze mid-gesture. Then gave a short, incredulous sniff. “Honestly. I shouldn’t even be surprised anymore.”
Cho had the distinct impression that the professor wasn’t just surprised—she was impressed. And she knew perfectly what Harry Potter was working towards.
“My question is,” Babbling said slowly, folding her hands, “what exactly do you want to do with this information, Miss Chang? I assume you want to work on the same topic? Something to better your own chances? Or shall I say… Mr. Diggory’s?”
For a moment, Cho was tempted to say yes. If she succeeded, Cedric’s name might emerge from the Goblet. It could guarantee his selection.
But the hesitation in her chest said otherwise.
If Cedric couldn’t become Champion on his own, did he really deserve it?
Harry was rigging the odds. Unethical? Perhaps. But it was bold. It was clever. It was active. Cedric, in contrast, was doing what? Ranting about fairness. Screaming about injustice. Demanding the rules be rewritten because… what? He was afraid of losing to someone not yet past his OWLs?
Cho’s voice was calm. “Actually, I was thinking of joining Potter’s project. Given the scope of the research, I believe it would be stronger as a joint paper. Especially if the ritual is proven correct… it won’t just be theoretical. It will be a live demonstration.”
“If Potter’s name comes out of the Goblet,” Babbling finished, observing her shrewdly. “A very real possibility. And have you thought this through?”
Translation: Have you considered how this might affect your boyfriend?
“I keep my personal and academic lives separate, Professor,” Cho replied crisply. “If this succeeds—and if Potter is selected—perhaps we could submit it to the Lexicon Thaumaturgica?”
Babbling gave a low whistle. “That’s ambitious, Miss Chang. Very ambitious.”
Cho smiled primly. “It would certainly open internship pathways. For both of us.”
The professor considered that. “But you realize Potter chose this topic independently. You’re coming in after the fact. He may not be eager to share the spotlight—or the credit.”
Cho tilted her chin. “I’m confident I can be… persuasive.”
Babbling arched one brow in amusement. “I see.”
Cho smiled. Her owl Inari was up for a very busy night.
....
....
Cho approached him the next evening.
She waited until just before dinner—when the library was half-empty and the dimming light slanted perfectly across the table he’d claimed for himself.
He looked up when she sat down.
She said nothing at first. Just placed a small folder between them.
“What’s this?” Harry asked, not yet touching it.
“Proof that I’m not here to waste your time.”
He opened the folder. Read for less than a minute.
Then met her eyes.
“This is family research,” he said quietly.
Cho nodded. “I told you. My family’s lineage traces back to Far-seers of the Han dynasty. That scroll contains unpublished notes on recursive fate-binding matrices derived from the Southeast School.”
Harry gave a low, appreciative hum. “And you’re just offering this?”
“I’m offering a partnership,” she said. “I know how to read these materials. I can match your pace. And if we co-author the paper, your name goes first.”
He raised an eyebrow. “That generous?”
“I want this published in Lexicon Thaumaturgica,” she said. “And you’re the one with the story. I’m the one with the credibility. And if your name truly comes out of the Goblet, we will have evidence.”
Harry looked back at the scroll.
After a moment, he closed the folder and leaned back.
“Alright,” he said.
“Obviously, you’d need some time to think over this, what with me being with Diggory, which is why I brought that paper as proof of my sincerity. If you agree to this, we can have an official partnership document set up by an attorney. I’m guessing you already have one, and if not then, my family can definitely — wait, did you just say alright?”
Harry just looked at her in amusement.
“I did.”
“Ah. Well, okay then. I’ll owl my family.”
And Cho, for the first time in weeks, felt something electric beneath her skin.
This wasn’t just an academic gamble.
This was a wager. A dance. A step onto a board where the stakes had already changed.
And she’d just made her move.
....
....
The thing about runes is—they look cold. Carved stone. Etched lines. Unyielding, unfeeling logic scribbled into permanence. But that’s only the surface.
Underneath, runes are hungry.
They crave attention. Understanding. The right frequency of intent. And if you get the resonance just right, they sing.
Not that I’d admit that aloud. Not even to Hermione.
Especially not to Hermione.
I leaned over the layered rune matrix, tapping my quill against the corner of the parchment. Next to me, Cho Chang adjusted a scroll of ancestral patterning from her family library, her hand brushing mine for the fourth time in ten minutes.
It wasn’t an accident.
Hermione had, unsurprisingly perhaps, let me work with Cho alone. Between her own lack of depth in the subject, and that werewolf aggression at seeing some other woman (threat) sitting next to me, Hermione would go crazy.
She might even react badly against Cho.
Or start forcibly making out with me in front of her.
Either or really.
But most importantly, she knew what I was doing, and why.
Still, that didn’t mean we got to work in silence. The moment Cho started working with me, news spread around. As it was, a few fifth and sixth-years were sitting farther down the table, pretending not to eavesdrop. Lavender Brown had taken a spot opposite me, trying very hard to pretend to do her Charms homework, while sneaking glances at Cho. Then at me. Then back again.
I could practically hear her curiosity humming.
Cho and I had spent the last few days syncing our notes—her Eastern matrices were compatible with my recursive Perthro-Algiz structure, and together they could build something terrifyingly effective: a fate-locked runic loop that could, theoretically, force a ritual to produce one and only one result.
Of course, every ritual had its own eccentricities, which meant figuring extra variables, but if this worked, well… the Goblet of Fire wouldn’t know what hit it.
But this wasn’t just about magic.
It never was.
Cho leaned closer. Her perfume—not overwhelming, just that faint whisper of peony and winter plum—brushed my senses. She reached across me for a sheaf of notes, her shoulder grazing mine, and this time, she didn’t shift away.
I let my hand rest, motionless, between us under the table.
She stilled. Then, slowly, let her thigh slide just enough to touch mine.
It wasn’t flirtation anymore.
It was negotiation.
I’d been careful with her. Careful with everyone. Since I’d started noticing the way people reacted to me—how heads turned when I walked past, how eyes lingered longer than they should.
But trust me when I say this. That was me… restraining myself.
I’m not human. Actually, I’m not quite certain if I’m even a wizard anymore. I’m an Incubus Lord, a creature of lust. An apex sexual predator. One that would relish in unleashing my restrained madness into all of Hogwarts and turn it into a giant orgy, while I fed and fed and fed.
Trust me, my hunger stirred every single time her skin touched mine. The demon gleefully danced for a heartbeat or two, and as it did, Cho shivered, her heart rate rose, and her pupils dilated. My Allure told me what it always did about her. Though she looked all proud, focussed and oh-so-ambitious, in reality, she was a repressed bitch that needed to be shown her place. Fingers tightening in the back of her hair, feeling my body press hers against a wall — that was the stuff of her fantasies. She would follow me to an unused classroom without hesitation. I could take her there. I could fulfill all her desires, feed my Allure, draw away her life, and take my fill. I could leave my mark ripped into her mind so that forever she would come to me willingly, eagerly, yearning to be taken again and again and agai—
Until she died.
I pushed my allure back down into the corruption that passes for my soul, and I smiled at her.
“You misaligned the frequency markers here,” I said, pointing at the script. “If Perthro intersects with Algiz at a cross-angle this sharp, the resonance will collapse.”
“I wanted to see if you’d catch it,” she replied.
She was lying. She didn’t care about the resonance.
Not right now.
“Let me correct that,” I said.
Our hands touched again.
She smiled.
I felt her mind slip into idle fantasy as the thin warmth of her presence pooled around the point of our contact, sliding up into me. My inner demon screamed for me to do more, to take more, that it wasn’t enough. But I didn’t. Feeding would have been … delicious. But it might have hurt her, too. It might even have killed her.
So I kept on with the pretense. Somedays, it was more difficult than others to hold back. But it’s what I do. The Oneiros Spindle helps more than you think. The Spindle needs power — raw, emotional power —to fuel it, and I let it guzzle up my allure, storing it until dreams release it like steam.
But allure is only half the danger.
The other half… is influence.
I could seduce anyone in this castle with a whisper, if I wanted to. I could sleep with every woman in this castle, students, professors even — and they would do it without even the slightest hesitation.
But here’s the thing.
I don’t want thralls. I want Lilims.
People who choose me. Who devote themselves willingly, completely—without being bent by compulsion. That’s the difference between power and belonging. One takes. The other offers.
Which is why I’ve learned to seduce the slow way. The human way.
Let them come to me. Let them want it.
Cho’s leg pressed more firmly against mine now. Still subtle. Still deniable. Her quill moved across the parchment, but her posture said something else entirely.
I let my foot drift.
Just a brush. Barely there.
She didn’t flinch. If anything, her lips parted slightly.
Lavender saw it. Then looked back down at her own parchment, pretending to be immersed in her homework.
“Let me correct it then,” I began slowly making changes to the rune matrix, and pressed closer against Cho, my left hand gently landing on her upper thigh. Her blush intensified, but she made no attempt to acknowledge it. Taking that as approval, I started to caress her toned legs, slowly climbing upwards.
She lifted her heel.
“See this? I think this works a lot better, don’t you think?”
A thin cutting hex made a neat gap through her skirt, letting my hand wander inside.
“Oh my,” said Cho, her breath changing tempo. “Yes! Yes, it — it does!”
Right then, I noted that Lavender had given up all pretense, and was gazing at me. One could even call her gaze hungry, and no, it wasn’t because of my Allure, passive or otherwise. Her mouth was open in disbelief, her eyes so wide that I could throw a psychic dart in the dark and still hit them. I sensed indignation, disbelief, and more than a fair bit of jealousy, with generous amounts of excitement rising from her loins.
I met her gaze, widening my smile just a little. To her credit, she didn’t blush, react or look away. Her body, though, gave her away. She crossed one leg over the other, leaning ever so slightly toward me.
It made me smile.
I slid my foot across to Lavender.
Just the edge of her ankle.
She jerked—barely—but turned to glance at me, brows raised.
I met her eyes.
No smile. Just calm permission.
Her lips twitched.
Then, to my surprise, she uncrossed her legs… and let her foot slide toward mine.
Two girls. One table. All of us still scribbling notes. The lanterns above us spun slowly, casting pale light over ancient texts and far more modern tension.
I wasn’t using magic.
This was all consent.
All tension.
Cho adjusted in her seat, her thigh nudging mine more deliberately.
What an attention hog! I told myself. Inwardly laughing, I gave in.
"If you rotate the base node of Algiz thirty degrees," I whispered, my fingers crawling across her leg in a generous arc onto her rump, letting my fingers sink a little into her supple flesh. She jerked a little, her mouth opening in shock a little. “It redirects the intensity.”
Cho widened her legs just a little. ‘But — but if you open the protective fold…”
“Ah, I see,” I played along, my fingers crawling to her front, resting on her thigh, slowly climbing higher and higher, until she could feel them on her underwear. “I suppose, if we add a Perthro in the loop…”
With a flex of magic, her underwear vanished.
My leg climbed up Lavender’s knee.
Cho shivered. “I — I guess it stops being random luck.”
My hand rested on her naked pussy — shaven too. Nice.
My leg… crawled up Lavender’s upper thigh. She opened her legs just a little.
“It becomes intentional,” she said, her face shifting colors from faint pink to deep red.
I caressed her slit, and passed a little of my charm through my feet, activating Decadence Link.
“Guided chance,” I finished. “Chosen fate.”
My finger dug in, her hotness enveloping my skin.
“YES!” Cho gasped loudly, not expecting the sudden penetration, and realised that she had voiced out loud. Too loud. “I mean, yes, yes, of course!”
Lavender didn’t listen. She was too busy bending forwards, oblivious that she was giving us a generous view of her bosom, too caught up in the feeling of her clit crushing against an invisible finger that wasn’t there.
“Are you okay, Lavender?” I asked in fake concern.
“Yeah,” she managed to stammer. “I just — it’s just cramps!”
“Must be,” I said, playing along. “You looked distinctly uncomfortable. Must be the dinner.”
“Yes! The food!” Lavender agreed, still addled in the sudden pleasure, unable to realize how unconvincing she was being. Not that Cho minded. She was too busy bending forward, doing her best to write, but actually closing her eyes, trying to contain the pleasure invading her whole being.
It didn’t help that I was constantly plowing her fields with increasing speed.
You know what? Maybe doing this the hard way might have some benefits after all.
....
....
Cedric Diggory was good at keeping his composure.
That was what everyone said. Professors, classmates, even the passing portraits. "So composed," "A model Hufflepuff," "Reliable and fair." He wore those words like armor. Smiled when expected. Nodded when appropriate. Played fair, even when it hurt.
Today, that armor cracked.
The Dueling Club was packed. A dome of noise, nerves, and the slow, simmering buzz of gossip. Ravenclaws leaned over the balcony with hawk-like curiosity. Slytherins lounged below with shark grins and folded arms. Even some Gryffindors hovered at the edges, sensing blood.
This wasn’t a scheduled duel.
It was personal.
Callum Rosier stood at the opposite end of the platform, wand twirling lazily between long fingers. His robe collar was open, sleeves rolled halfway up. All pretense of formality discarded. He wore his arrogance like a second skin, and his smirk screamed: I’ve already won.
Professor Flitwick raised his hand.
“Begin.”
The spell came faster than a heartbeat.
“Expelliarmus!”
Cedric’s shield flared a moment too late. The disarming spell clipped his shoulder and jarred him, but didn’t take his wand. He recovered, planting his feet.
“Flipendo!”
Rosier parried, spun sideways, and returned fire with a wordless stunner.
“Protego!” Cedric barked.
The scarlet flash sizzled off the barrier and scorched the ground. He countered, rapid-fire—“Petrificus Totalus! Impedimenta! Reducto!”—testing Rosier’s guard.
The Slytherin deflected two with his shield but the force of the reductor spell passed through, hitting his knee. He stumbled, but turned it into a dramatic twirl and threw a cutting hex in response. It clipped Cedric’s left cheek, and he winced as something sharp pricked under his skin.
“Episkey,” he hissed quickly, wand-tip tapping the sore spot. He slipped to his right, timely avoiding a cutting hex, before hurling a stunner, which bounced harmlessly off Rosier’s shield.
"You duel like someone afraid to mess up his hair."
Cedric ignored the barb. He moved into transfiguration tactics—flicking his wand in a crescent. The floor beneath Rosier shifted, turning slick and icy.
Rosier’s boots skidded—barely—but he compensated with a levitating charm. His feet hovered just above the surface as he hurled a volley of Reducto curses Cedric’s way.
Cedric dodged, ducked low, and answered with a loud, “Expulso!”
The blast cracked Rosier’s floating stance and sent him stumbling midair, but he caught himself.
“Wow, that one almost hit me,” said Callum. “Maybe if you worked on that instead of polishing your wand, your girl would still be yours.”
…what?
“CONFRINGO!”
The force caught Cedric off-guard and knocked him back. He landed hard, his elbow smacking against the platform. A sharp sting ran up his arm. But worse was the murmur from the crowd.
And then Rosier struck home.
“Funny,” he said, too loud. “You threw up all that ruckus. Gathered a following to scream against ‘injustice’, and your girl voiced for Potter instead!”
Cedric’s head snapped up. “What did you say?”
“Oh, come on. Everyone knows. She’s been with him every evening this week. In the library. In the corridors. Laughing. Or maybe the nights too.”
Cedric froze.
It was only for a moment.
But it was all Rosier needed.
“BOMBARDA!”
The Blasting Curse slammed into Cedric’s half-raised shield. It shattered. He was thrown across the stage like a rag doll. His wand tumbled from his grip. His back hit the barrier wall with a sickening thud.
The platform went quiet.
“Accio wand,” Rosier murmured, catching Cedric’s wand in his free hand. “What’s the matter, Diggory? Not used to losing your grip?” He paused, then added with a sneer, “Once on your wand. And once on her.”
The silence broke with a ripple of murmured laughter. It was cruel, muted, but it carried.
Cedric lay on his back, chest heaving. He couldn’t even feel the sting in his arm. Not over the slow-burning rage and the deep, bitter ache of humiliation.
Rosier turned on his heel and walked off the platform, arms raised like a champion.
Flitwick finally moved, kneeling beside Cedric and beginning healing charms. “You’re concussed. Let’s get you to—”
“No,” Cedric muttered. “Just… give me a minute.”
Zacharias Smith knelt nearby. “He’s a git. But he’s not wrong.”
Cedric glared.
“She’s been with Potter. A lot. Laughing. Studying. Everyone’s seen it. I thought you knew.”
He said it like a courtesy, but it landed like a punch. It was true that Cho had been pissed off ever since he had been publicly humiliated in a duel he had started. That it had been three against one went completely against Hufflepuff ideology of fairness.
That he was a sixth year, facing off a fourth year hurt his reputation.
That said fourth-year had handed him his arse without breaking a sweat made people start wondering if he was truly as capable as his reputation claimed.
He knew that Cho had been… distant lately, but he had told himself it was because his brazen behaviour had upset her very much. After all, the one thing Cho Chang loved more than everything else on Earth was her stellar reputation, and his actions had not scored any points with her.
Especially in the light of the stern warning he had gotten from the DMLE.
And if she thought that his actions had cast a shadow on her, was that why she was…
She was….
He couldn’t bring himself to even think it out loud.
“Diggory…” Smith began, but Cedric waved him off, pushing his hand away, and standing up slowly, wincing at the pain in every joint of his body. His hand clenched and unclenched around the wand Rosier had tossed back to him as he left.
Silently, he trudged out of the Charms classroom. But he wasn’t headed to the Hospital Wing, or even the Hufflepuff common room.
But to the library.
He didn’t mean to arrive there. He really didn’t know what he would do.
But he had to see.
He stepped inside.
The hush of parchment, the rustle of turning pages, the scent of candle wax and ink. And then in one corner, he saw—
Cho. And Potter.
Far back, beneath the tall windows. Her head tilted, her body uncomfortably close to him, a content expression on her lips. Potter leaning back, listening. Not smiling. Just watching her like he didn’t need to do anything more.
Cedric didn’t move.
Cho brushed her hair behind her ear. The same way she used to when she spoke to him.
He didn’t speak.
He just watched. Long enough to feel it set in stone.
Because Cedric Diggory—Hufflepuff’s golden boy—had just been bested, broken, and replaced.
And it burned.
Comments
Hadrian v.E.
He's too arrogant to take freebies 🤭.
Hadrian v.E.
I wait for new weekly chapters of this story with great eagerness, and this one is most certainly deeeeee-licious!
Heroville111
I love that you found a way to make harry abusing his power to sleep with women into a negative so that he still has to earn it to make them his lillium
