October 9, 1976 — Hogwarts

The autumn wind was picking up, the Forbidden Forest gaining a golden-red sheen. It rained more days than not, great shadowy clouds in the sky. Today was almost warm, a scarce treat for Scotland in the throes of fall.

Bundled in the scarf Cassiopeia had made for his birthday and a coarse woollen coat, Severus sat on the grass, his expression contemplative as he regarded the textbook in his hands. The margins of potions recipes were scrawled over with his script — various improvements, little notes to himself. Somehow, the book had become a source of inspiration to him, a private trophy to his capabilities.

He tried to strike the balance between false modesty and foolish, unwarranted pride, and in this he admitted to himself that potions were his specialty, his skills in the field advanced far beyond his age.

He smiled slightly, allowing himself to do so away from prying eyes, smoothing his fingertips over a page. The second-last to be annotated, it held his biggest source of pride as of the last weeks — a new spell, the second of his inventions that had ever worked.

Failed attempts lined the pages of his book, too numerous to count. Yet now a spell, and a counter to it as well — unlike Sectumsempra, with whose countermeasure he'd had little luck.

He closed the book with a satisfying snap, resolving to enjoy the quiet lapping of the Black lake for just a moment more before he went inside, facing the draining politics of Slytherin House once more.

"Enjoying yourself, Snivellus?"

He sprang to his feet, his lips bared in a snarl. Even without that goddamn map in his possession, Black always managed to corner him when he was alone – somehow appearing in front of him out of thin air. And this time he'd brought a friend.

Severus didn't bother responding to the smug taunt, instead sending a volley of spells at the pair – focusing his energy on Black, who was at least proficient in casting, unlike the bumbling coward at his side.

He didn't like the sudden gleam in Black's eye when the Gryffindor put up a shield around himself, stopping his offence. "You know, Snivellus, Peter just taught me the most interesting spell – "

"Levicorpus!" – "Expulso!"

He couldn't block two curses at once, and even as anger surged within – how dare they use his own spell against him! – he knew which one he had to choose.

His breath left his lungs when he was suddenly, sharply hoisted in the air – the incantation clumsy in that bastard's mouth.

"Scourgify!"

He choked suddenly, the words to the counterspell lost as his mouth filled with harsh, chemical soap, the bubbles sliding down his throat as he coughed, his eyes watering. He couldn't breathe –

In a second, however, the force of his magic, even if he couldn't speak, dropped him onto the ground – his shoulder exploding in pain as he fell onto a rock – and he spat the soap onto the grass, his expression filled with hatred. Pettigrew, startled, stepped back.

His muscles were stiff, the grip on his wand unbelievably tight as he stared into that amused expression of Black's, barely hearing the words he was saying through the rushing in his ears.

"...Lily's been asking James to go easy on you, you know. She feels so bad for the poor, slimy snake; so pitiful – "

No. Never pity. Never that. A wave of fury rushed through him, leaving him breathless, his vision narrowing on that hated face. Black was talking, blathering on about Lily and James, about how much they loved each other, but Severus was focused on the wand in his hand, and the curse on his lips –

No, Black couldn't know.

"Mogrifian," he whispered harshly instead, letting his wand channel his hatred, his enmity. Dark ropes burst forth from his wand, wrapping around Black like great ribbons of fire, each bringing with them a searing pain. He heard Black scream, saw him lifted into the air by the force of his magic. The spell whispered to him – just a little more, and the reminder will be marked on his skin forever. Just a little more, and he won't remember anything again.

It was that last thought that pulled him back, gave him the control he needed to ease the spell, let the ropes become little more than tight, painful binds. He watched dispassionately as Black panted, coming down from the momentary agony, his grey eyes filled with anger and fear. Delectable fear.

Pettigrew had long since fled. Expectedly.

"How foolish…" Severus murmured, concealing the tightness of his throat, the clenching of his fists. "You forget I am not so easy of a target when not outnumbered."

"Let me down," Black hissed in response, struggling in the air like a fish gasping for oxygen. "Dark Magic – just like everybody knew. You'll be expelled."

"Will I?" he asked mildly. Power. This was what he craved. "I think not, Sirius."

"You think Dumbledore would let you off for this?" Black laughed, aiming for nonchalance when it was so clear he feared his subservient position, feared the revenge the Severus so acutely sought.

"Oh no. But who said the Headmaster would ever know?"

"You don't think – "

Severus knew there was little choice in the matter, if he wished to keep himself in school, and out of Azkaban, perhaps. Never mind that this was nothing – nothing compared to Black's attempted murder, an agonising death by feral consumption.

He dropped Black to the ground, keeping him bound as he stood over him, watching the terror play out so unmistakably over his face.

"Obliviate."

It was an intricate spell, advanced, but the great Dumbledore had taught him a thing or two. In moments, Black's memory of the spell was smudged into nothing but a heart-stopping moment of utter fear.

Slipping into his mind briefly, he placed inside a compulsion to never mention Severus' retaliation, and to keep it concealed should he be Legilimised.

This too, he had learned from the esteemed Headmaster.

Withdrawing from his mind, he knocked out Black with a particularly vicious Stupefy, allowing it to channel his rage, before leaving him half-tied, lying there in the grass.

Cassiopeia watched Severus from the corner of her eye.

He had swept into the common room, all imperious and incensed, but she noticed the uncharacteristic inelegance of his stride, his lips twisted into a savage snarl, a burning fury in his eyes.

She did not greet him as she usually did. Severus had always been the one of them quickest to anger, the easiest to antagonise into wrath. Yet there were few moments now when the interplay of emotions was so clear on his face, when fiery feeling thawed away the cold mask.

Dangerous, her mind whispered in warning, but she quelled the momentary discomfort. She had known of the darkness that lurked in Severus for years now, had accepted it as a part of him in a way that Lily could never have.

She just knew he would not want her now – that their ways of comfort were diametrically opposed.

Some time later – she couldn't be sure, for darkness now cloaked the common room from early afternoon – she came to him, standing in the doorway to his room, waiting to see if he'd allow her in, or kick her out.

He did neither – remaining hidden in his bed – so she made the decision herself, closing the door quietly and pulling open the curtains that concealed him. He was lying asleep on the mattress, his hair strewn across his pillow. She would have smiled at the vision, were it not for the sight of a bandage wrapped inexpertly across his shoulder, and the vial of half-empty pain potion that stood on his shelf.

She was surprised that he had not already awoken, but she'd known he'd been getting little rest since they'd returned to school, and at the Manor. It was obvious to everyone who knew him that Severus was a bad sleeper at the best of times, but his bouts of sleeplessness only grew worse when he was stressed.

She was loath to wake him, but blood was beginning to seep through the bandage, so she touched his shoulder lightly, watching as he gasped, startling awake.

"Cassiopeia?" he asked, blinking open his eyes, long eyelashes standing out in contrast against his skin.

She gave a murmur of confirmation, and although he was almost fully awake, she kept her hand on him, so he would not rise.

"Your bandage is soaked," she explained. "Let me redress the wound."

After a moment, he relaxed into the bed, and she forged ahead, carefully prying the sticky gauze from the deep laceration it covered before scourgifying it multiple times and treating it with a healing spell she'd learned, to disinfect it additionally. She reapplied it, wincing in sympathy as Severus hissed, before she secured it, letting out a breath she hadn't realised she'd been holding.

"Who did this?" she asked a moment later, and heard Severus snort derisively.

"A rock."

"Really, Severus?" she asked, her brow arching skeptically.

"Directly, yes. Indirectly, it was Black's fault… And Pettigrew's, I suppose, though the coward cast one spell and fled."

"That's more than I'd have expected, honestly," she laughed slightly, before her tone turned considering: "Though I think he might be getting private tutoring from Professor Sayre – I've seen him in her office a few times on the Map. But – " she shook the thought away, " – what happened with Black?"

"What always happens," he replied bitterly. "He cornered me and got a few hits in… used Levicorpus against me – "

"How on earth would he know about that?"

"I don't know," Severus answered tightly. He seemed angry, but lying face-down on the bed took a lot out of his frightening image. "I've only ever practiced it a few times outside of Slytherin, and it was on the grounds. I would have known if there was someone watching."

"You know – we never did try to find out if Pettigrew was an Animagus also."

Severus let out a disbelieving laugh. "Pettigrew? The lumbering imbecile who can't do a drop of thinking for himself?"

"He could have an inclination for it," she mused. "To some people it comes naturally, no matter of their skill."

"Cassiopeia…"

"It's just a theory," she admonished lightly, amused by the appalled expression on his face. "But we'll probably never find out, so it doesn't even matter."

They lapsed into silence for a moment, before Severus spoke. "Has he been antagonising you at all?"

She shook her head. "Nothing quite serious, just the usual taunts, you know…"

He raised his brow, and she narrowed her eyes.

"Severus, you're well aware of what Black's favourite epithet for me is. He's taken to using it as often as he can."

His expression grew dark, his lips twisting into a snarl. "...It's not even true."

She paused, her muscles growing a little stiff. "You don't think so? Cailean and I…"

His eyes widened, and she wasn't sure whether it was due to her admission, or the self-deprecation. "...Merlin, Cassiopeia, it doesn't matter how many people you've slept with, you're not some fucking harlot. He has no right."

She shrugged, suddenly uncomfortable with the force of his attention on her, even if she agreed – even if she wasn't sure why she'd even brought the topic up. "Others might not think so."

"Since when does that matter?" he asked, his tone a little gentler.

"If I ever want to get married, some men don't want – "

"Any wizard worth your time wouldn't care in the slightest," he interrupted firmly, and she was surprised by the passion in his voice, even as his expression turned to self-consciousness as he grew aware of his tone.

It was a few minutes later that Cassiopeia realised he'd be one of those wizards, if his admission was true. The thought filled her with an unexpected thrill.

October 9, 1976 — Hogwarts

She gritted her teeth, parrying Severus' barrage as quickly as she could – overcoming her instinct to cast defensively. They'd been practicing for an hour now, ensconced in the seventh-floor classroom, and though she could hold her own for some time, in the end their duels always ended with her disarmed, or lying on the floor, Severus' wand at her neck.

Casting was instinctive for him, magic flowing freely from his wand, his movements graceful and easy. She, on the other hand, was forced to focus on all aspects of her technique – evade or shield? Advance or retreat? Distract? Harm?

In the end she would slip up, and Severus would press his advantage well.

"Protego Diabolica," she blocked Severus' attack, but as the cursed flames exploded around her, she felt them being overwhelmed, absorbed, and in moments her protective barrier began to move towards her, the heat burning her skin.

She fought back, but Severus' control over her own spell – and she had no idea how he'd managed that – was stronger. It was only when the flames threatened her robes that he ended his casting, dissipating even the fire that had been hers.

"You won't survive like this," he said scathingly, even as he walked over to her, making sure she had not been harmed. "Any adult wizard – you'd be gone in a few minutes at most."

Though his words were harsh, she sensed the undercurrent of concern in his voice, knew that this was fear of her injury or death expressed in the unconventional, Severus way – when his pride, his personality knew no other way to articulate it.

"We'll put aside time to practice more."

Severus frowned. "Yes. But that won't be – " he cut himself off, seeming frustrated. "That spell was Dark Magic, or as close to it as we can perform within the school. You had good control – "

"You took over immediately," she interrupted, disbelieving.

"Yes," he responded irritably, "because the spell knew you didn't want to actually hurt me. You need to learn – ruthlessness. Otherwise all your even semi-dark spells will be weak."

"If – when I'm actually fighting, I will want to cause harm."

"You need to learn before that. If you could duel someone you hate, or even dislike – " he paused, considering. "I'm… reluctant to suggest it, but I think you should come to the Duelling Club. Even if only once."

She frowned for a long moment, regarding the expression on his face. "...I'll consider it."

"Please, do."