Cassius stood outside his father's office in the dungeons, the air thick with the familiar scents of damp stone, bitter herbs, and lingering potion fumes.
Most students avoided this corridor at night—Professor Snape's presence alone was deterrent enough—but Cassius had grown up in an even more suffocating environment than this.
This level of intimidation and darkness?
Please it was a walk in the park to him.
Comforting, even.
But he wasnt here for the pleasant ambiance.
He needed Severus.
And Severus needed to understand something he clearly had not yet accepted, or was choosing not to acknowledge.
Cassius knocked once.
A clipped voice answered instantly.
"Enter."
Cassius slipped inside.
Severus Snape sat behind his desk, framed dramatically—of course—by the flickering candlelight.
His black robes draped around him like a shadow given shape.
His expression was its usual mask of icy irritation.
But his eyes flicked up briefly in a way Cassius recognized.
Concern.
Hidden.
Buried.
Desperate not to show.
"Cassius," Severus said, voice dry as chalk. "If you're here to ask about the composition essay, I already told your class it is due next Tuesday, not—"
"It's not about class," Cassius said as he closed the door behind him.
That made Severus pause.
Very slightly.
Cassius stepped forward.
"We need to talk."
Snape's eyebrow twitched. "A phrase that never precedes something enjoyable."
Cassius ignored the prickly tone.
Both of them knew it for what it was—deflection.
Shields.
Distance.
He walked up to the desk, pulled out the chair opposite, and sat.
"Father," Cassius began calmly, "your allegiances need to change."
Severus went utterly still.
This was afterall the first time that Cassius had gone outright to refer to him as father, and as much as he didnt want to react, his wish was indeed granted.
Hear the words spill forth from the boys mouth caused the seasoned veteran to freeze up.
The flames crackled as if they knew to go quiet for this.
"…I see," Severus murmured, tone glacial. "And you believe you are in any position to dictate my allegiances?"
"Not dictate," Cassius corrected. "Point out the obvious."
Severus's eyes narrowed. "Do enlighten me."
Cassius leaned back, crossing one leg over the other.
"Your tie to Voldemort is already severed. Your dark mark was cleansed back then, and a trap lain on what remained. At this rate The dark lord would be left to believe that thanks to my actions, that you are a traitor to his cause."
A flicker of movement—the smallest tightening around Severus's mouth.
Cassius pressed.
"Basically you're free from his cold embrace, and free to choose your own course once more."
"I," Severus said sharply, "am never free of the Dark Lord. Do not be foolish. The man does not tolerate—"
"You are free," Cassius repeated, his tone a quiet hammer. "You've been free for three years. You just haven't embraced it, and sure he might retaliate in the future... but thats in the future you'd have years to plan against his return, and even if he does and you can't win, then just run go somewhere else, whats he gonna do hunt the whole world down looking for you."
Severus's hand curled slowly around a quill.
"And what," he said in a dangerously low tone, "could you offer in return, afterall i serve the greatest sorceror in the world?"
Cassius didn't flinch.
He set a parchment on the desk.
The contents of this parchment were enchanted to be viewable by one man only and upon its full reading the parchment would auto-incinerate.
But more than that, even though Cassius trusted Snapes own occulemcy he never fully could come to trust dumbledore.
So woven into the knowledge was a trap spell to obliviate the knowledge should it ever be prodded by an outside force.
Severus stared at it.
Eyes straining to resist the urge to shoot wide open.
Cassius said, softly:
"I am the student of your current Masters Nemesis, i am his ward effectively, and as such as hold his will in my hands, the world is changing and when it does i'd like to have you standing by my side supporting me, rather than standing against me."
Silence.
Severus did not speak.
Did not breathe.
Did not blink.
Then slowly—slowly—he inhaled.
"...I see, and what just because of this you think i should give up years of loyalty?"
Cassius shrugged lightly.
"Fine, just know i've been winning the hidden struggle for years now."
Severus's eyes flashed. "Winning, how can you—"
"Yes, if you read on, the rest will surely enlighten you" Cassius quipped.
He leaned forward, bracing his elbows on the desk.
Severus stiffened like he'd been slapped.
Eyes darting down before continuing to read what was before him.
His head sweating the more of what he read.
Cassius continued, unwavering.
"As you can see, the future belongs to me, and i will make it happen, neither side in the previous war had the right to win, and The current dark lord... his will is just a pale imitation to my master, but my own ideals, they can be achieved, and the world saved as a result."
Severus whispered, "You are playing with fire."
"Dragons fear not he flames."
That line made Severus blink.
Cassius lowered his voice.
"The Arcanum is mine, but on the otherside, i already control a good stake of their world as well, school is just a growth medium for me, by the time i graduate i'll be ready to make my move."
Severus's heart clenched.
Physically.
Painfully.
Cassius saw it.
Pressed harder.
"Sirius and Lupin both ow me life debts, while the girls of my house here at school are bound my magical covenant even after we leave school. The Arcanum is opening the eyes of wizards and bringing them into my fold, while the Muggle world is being prepped for the emergence of magic. When the 'war' happens it will be a slaughter of those stubborn enough to cling to the old ways."
Cassius's eyes locked on Severus's.
"And i dont want to see that happen to you."
Severus swallowed.
Audibly.
~
Inside his mind:
Say yes.
Say yes right now.
Agree.
This is what you wanted, you miserable sod.
He wants you.
He's choosing YOU.
~
Outwardly:
Severus sniffed disdainfully and looked away.
"Hmph. Ridiculous. Overdramatic. You're just a child, even if everything you say and wrote is true you'll never pull it off."
Cassius smirked.
He had long since known Snapes personality type, seeing him 'resist' as he was now was like watching him dig his own grave.
~
Inside his head:
My boy is to great.
Master of all he see's.
Future ruler of the world for all anyone cares.
~
Severus froze.
Completely.
His breath caught in his throat.
For a terrifying moment Cassius thought he'd pushed too far.
Then Severus spoke—quiet, brittle, and unbearably human.
"…I want to," he confessed.
Cassius didn't react outwardly.
Inside, victory tasted sweet.
Severus cleared his throat hard—too hard—and straightened.
"But," he said sharply, snapping the vulnerable moment shut like a slammed book, "I have conditions."
Cassius raised an eyebrow.
Of course he did.
"Name them."
Severus stood up, crossed his arms in the dramatic fashion he undoubtedly practiced, and declared:
"If I am to commit to this… organization of yours… then you, Cassius, my... son, will dedicate an additional three hours per week to potions."
Cassius blinked.
"…Potions?"
Severus nodded stiffly. "Advanced work. Personal tutoring. No complaining."
Cassius stared at him.
"That's your condition?"
"You are barely average at handling ingredients," Severus lied through his teeth. "If you are to lead anything, you cannot be incompetent in foundational disciplines."
The look in Snapes eyes was practically frantic, hoping he wouldn't refuse the kindest offer he could come up with on the spot.
Cassius held back a laugh.
"Fine," he said.
Severus blinked once.
"…Fine?"
"Yes."
Severus sputtered. "You—you agreed that quickly?"
"You wanted me to refuse?"
"No! I—I mean—Of course not. I simply—You—Hmph."
He turned away sharply, robe flaring as if he'd practiced the motion for dramatic effect.
Cassius suppressed a fond sigh.
"So," Cassius said, voice warm, "you'll join me?"
Severus paused.
Shoulders stiff.
Head bowed just slightly.
Then—
"Hn. If I must," he muttered.
Cassius smiled.
"Welcome to the Arcanum, Father."
Severus sniffed.
"Do not make a fuss. And don't expect any good tidings between the mutt and the wolf."
Cassius smirked. "Oh, I wouldn't dream of it."
Severus was bound to get a new round of teasing from his schoolhood chaps, for his change of allegience but that would pass with time.
Job done, Cassius rose from his seat and left the private office behind.
~
However within the office, the Potions master remained standing staring at the door his only son had just walked through, he could help but want to follow after him.
But no... that wouldnt be right, not proper... he had an image to uphold afterall.
And besides codling the boy now would do him no good anyway.
Severus Snape sat down, exhaled shakily.
Inside his mind he was in turmoil.
He had just agreed to betray dumbledore.
But if he stood opposed to the old man... what about Lily?
She was on his side as well, if he stood opposite her once more... would his heart need to be shattered twice in the safe lifetime?