The morning after the six-witch siege of his bed, Cassius woke sore, mentally exhausted, and absolutely certain of one thing:
He had made a mistake.
Several, actually.
And all of them were now standing in the training room of the draconis dormitory, wands drawn, eager, determined, and looking at him as if he were commander of a private army rather than a very tired third year.
"Welcome to the first session of Luminari," Hermione announced, quick-quotes quill floating by her head even though Cassius had absolutely not authorized note-taking.
"It's not a session," Cassius said. "It's a—"
"Meeting," Cho supplied.
"Gathering," Daphne argued.
"Battle prep," Ginny muttered.
"A bonding ritual," Luna suggested.
"A lesson," Astoria said.
Cassius pinched the bridge of his nose.
"Training," he said firmly. "Just… training."
The girls nodded in satisfied unison.
Merlin help him.
~
The door creaked open, and Remus Lupin stepped inside, robes worn but eyes sharp.
He carried with him a small crate the contents of which were a mystery to almost all of them.
But even though he was awed by his surrounding having been the first 'outsider' allowed within the dormitory thanks to receiving Cassius's permission to enter.
"Cassius," Remus greeted warmly. "And… all of you."
"Professor Lupin," the girls chorused back with a neatness that made Cassius suspicious.
Remus set down the crate. "I'll be assisting in your defensive regimen. Cassius is competent, yes—" he glanced at the boy with a small proud smile, "—but he is still a student. You need an adult instructor."
Cassius frowned. "I could—"
"No," Remus cut in gently. "You are leading them. You don't have to be the only one teaching them."
The girls all nodded emphatically.
Cassius glared at all of them.
~
Ten minutes into warmups, the door banged open with enough force to make Luna's hair float.
Professor Snape swept in like an irritated bat, cloak flaring dramatically.
"Professor. Cassius. Children." His eyes narrowed at Cassius. "Let's get down to business and see just what state you lot are in, and how large a task we have set before us."
"we're not useless." Hermione argued.
Snape stared at her like she had grown a second head.
Then he swung his gaze to Cassius.
"You requested my involvement," he said flatly.
Cassius blinked. "I did?"
Snape held up a letter — one Cassius recognized immediately as Hermione's handwriting.
Cassius closed his eyes. "Of course. I. Did."
Snape pocketed the letter. "If I am to be forced into this circus, I will at least ensure none of you blow yourselves up before summer."
Luna clapped quietly. "Yay batsy will make us become strong."
Snape stared at her.
Then he stared harder.
And wisely decided not to engage.
Catching the pitying shake of his own son's head off to the side.
~
Remus started them with spells Cassius knew were far above average schoolwork — deflection charms, silent casting drills, dynamic movement exercises.
Snape added precision demands and flawless wand control, correcting every misaligned flick and imperfect angle.
Cassius, to his internal horror, found himself stepping naturally into the role of combat instructor.
"Wands up," he ordered.
Six wands flew upright.
"Stances—wide, grounded. Luna, your shoulders."
She corrected instantly.
"Good."
They started with volley patterns.
Rapid-fire spell exchanges.
Controlled bursts of magic that forced the girls to dodge, block, and counter within mere seconds.
The room filled with streaks of blue and gold and white.
Hermione deflected accurately but still hesitated, to direct the incoming fire back at its source rather than just off to the side.
Daphne moved with fluid precision like she was dancing.
Ginny hit hard, too hard, and singed a practice target.
Cho focused her power tightly, every cast quick and sharp.
Astoria, surprisingly, had the ferocity of someone half her size and twice her intent.
Luna smiled the whole time — which was unsettling, even for Luna.
The first bruise appeared on Daphne's shoulder, courtesy of Remus's stinging hex.
The second when Ginny dodged too late and clipped her hip on a shield stone.
Astoria took a glancing hit to the thigh.
By the end of the first hour, all six were panting, sweaty, and dotted with minor nicks which would be mended in a heartbeat within the infirmiry.
"You're doing well," he said sincerely.
Snape, meanwhile, inspected them like ingredients he wasn't convinced were fresh.
"Barely acceptable," he said. "Again."
~
Two Weeks Later
Luminari met in the dormitory every evening.
Sometimes Remus taught.
Sometimes Snape.
Sometimes Cassius.
More often than not, all three ended up shouting instructions at once.
The girls improved with shocking speed.
Hermione stopped hesitating.
Cho learned to cast silently.
Daphne mastered shield-break patterns.
Ginny became terrifying with short-range stunners.
Astoria learned footwork that made her nearly untouchable.
Luna… well, Luna invented three spells that made Snape stop dead, stare, and mutter something about "experimental chaos tendencies."
Cassius, for his part, trained right alongside them.
Not one to pass up the opportunity to gain experience outside of his idle system.
And in doing so he could join in combat drills to develop teamwork between him and the girls even when on the battlefield.
Surprisingly enough Hermione was even willing to dedicate hours a day to training rather than studying.
Perhaps an effect of the AOE diadem or that she was absusing the Time turner to train and study at the same time, but she still looked healthy so he felt no need to interfere.
What would come next however was a pair of major events.
The first of which were the End of Year examinations, while the other was this years 'final exam' as created by Cassius himself to test the growth of the girls of Luminari to see if they indeed had the right to stand by his side, should 'anything' happen during the summer when they were hanging out with one another.
As agreed by all, if they passed cassius would not question their fighting by his side, while any who failed would not resist being sent off should combat against the dark forces occur.