Disclaimer - I own nothing you recognise.

All the love to the beautiful people who beta'd this, Amber, Ami and Abs. (A-Team for the win!)

Written for Hogwarts Secret Santa, for the lovely Sophie.

His

(except he's not)

He can feel eyes on him, following him as he walks from class to class. They bore into him whilst he's in the Great Hall, curious and burning, even though he does everything he can to ignore the feeling. He knows who it is, he knows he shouldn't do anything about it, but the temptation is there.

The temptation is everything.

He picks up on snippets of conversation about him, which all seemed to centre around how different he is this year. He's paler; he looks tired; he has dark circles under his eyes. He's surprised Dumbledore hasn't pulled him into the office yet, to ensure he's following the rules.

The old bastard knows what happened to him of course. He'd had no choice but to tell him, short of leaving school early, and that wasn't an option. The old man had cooed soft words of acceptance and compromise, lies that Regulus could taste, bitter on the tip of his tongue.

Even Sirius didn't know, protected from the truth by his absence this summer. The circle of people who knew could be counted on one hand, and Regulus wanted to keep it that way. But the eyes burning into him, brimming with curiosity, were pushing him to breaking point.

He roamed the school late at night, unable to settle into his dormitory like he used to. That was probably the hardest part of what he'd become; the lack of sleep. Regulus had always loved sleeping. Of course, the thirst was the other part he didn't enjoy, particularly when he was banned from fulfilling the need in him to drink the life from the people who surrounded him daily.

A friendly jostle, an accidental bump, every touch, every breath, every heartbeat lured him closer, tempted him to bite, to sink his teeth in and just drink.

Standing on a window ledge in the Astronomy Tower, Regulus looked over the grounds. He could see for miles around, unimpeded by the darkness now, though there wasn't much to see this night. The moon was bright in the sky, reflecting over the lake beautifully.

He supposed it would make a pretty picture, for anyone else.

For anyone who wasn't fighting every instinct inside themselves.

"Regulus? Why… why are you standing on the ledge? You should come down. You might… you don't want to hurt yourself."

Cursing himself for getting lost in his thoughts, he turned to look at the intruder, carelessly twisting on the ledge. If he fell, it wouldn't be the end of the world, after all. It's not like the fall would kill him.

The headboy, the owner of the curious eyes, was watching him with trepidation, clearly at a loss of what to do with the seemingly suicidal younger brother of his best friend. Regulus thought it would be safer to jump down, to offer meaningless platitudes that would stop the other from worrying.

But he was done with safe.

"How do you know that I don't want to hurt myself, Potter?" he asked, a smirk twisting his lips. "You've taken notice of my declining health since the return to school, have you not?"

"How did you…" Potter trailed off, his hand resting in the pocket Regulus knew carried his wand.

"You've been watching me, Potter," Regulus murmured, hopping down from the window ledge, landing lightly on the floor. He stalked towards James, the scent of fear and arousal stronger now, bringing Regulus' thirst to the forefront of his mind.

"You've been studying me, trying to work out what's wrong with me. Your eyes are drawn to me whenever we're in the same room, whenever we cross paths in the corridor. Admit it, James… you're a tad obsessed…"

"I don't know what you're talking about, Black," Potter managed to get out, though it wasn't snappy like Regulus was sure he'd intended. Instead, it came out breathy, unsubtle due to fear. "Sirius is worried about you, I was trying to find out what was wrong with you for him."

"You're lying," Regulus murmured, closer now, walking around James. "Sirius doesn't care what's happening to me. He's far too wrapped up in his pet werewolf to care about his little brother."

James blinked, taken aback. "How did you know about…"

"He's my natural enemy, of course I know what he is… the stench is unbelievable."

At first, Regulus had been fearful that Remus would recognise what he was, but it had all been for naught. Remus fought his creature so much, that he'd muted his instincts to almost non-existent. Stupid, in Regulus' opinion, since it stopped him from taking advantage of the traits his creature afforded him, but he couldn't complain, since it had worked to his own advantage.

Stumbling backwards, James' eyes widened. "You're a… a…"

"I always thought you were braver than that," Regulus taunted. "You can't even say it."

Quick as a flash he was behind James, his hands holding tightly at James' hips to stop him from moving. "But don't worry," he added, his lips ghosting over James' neck. "You won't remember."

The first drop of blood on his tongue was pure ecstasy, the forbidden fruit even better because he knew he shouldn't indulge himself. He sucked carefully, listening to the slowing of James' heart, the soft moans coming from the man held tightly by his hands. When James' head fell back to rest against Regulus' shoulder, he forced himself to pull away.

It wouldn't do to murder a student on Hogwarts grounds, after all.

Licking the wound to seal it, he carefully lay James against the stone, casting a warming spell over him.

Pressing blood covered lips against James' in a whisper of a kiss, he murmured, "Sleep Potter. You won't remember this in the morning."

As dawn brought the first rays of light to Hogwarts, the consequences of his actions battered Regulus' mind. He knew, he'd known while he was doing it, that he'd made a grave mistake in indulging himself. It was a weakness he couldn't afford to repeat, and as he dressed, he tried to convince himself that he could refrain from repeating it.

He could almost believe himself.

He sat at the Slytherin table, impeccably put together as always as he sipped at his coffee, waiting for the moment when James Potter would appear.

Sure enough, the black haired boy walked into the hall following behind Sirius and his boytoy, looking tired but none the worse for wear. Blocking out the rest of the hall, Regulus focused on them, watching from the corner of his eye as they sat down, the pathetic figure of Pettigrew bringing up the rear.

"I still can't believe you fell asleep in the Astronomy Tower," Remus was saying, shaking his head. "You do know you could have gotten in huge trouble for that, right?"

James shrugged it off, piling his plate high.

"Merlin, mate," Sirius said, watching his friend. "Hungry?"

"Starving," James replied, his focus on only his food. He didn't even pay attention when Evans took her usual seat beside him, and Regulus had to bite back a snarl when the red head pressed a kiss to James' cheek.

Feelings of possession filled him, his instincts screaming at him to break the girl's hands off so she couldn't touch what Regulus had claimed as his own.

He forced them down, averting his gaze completely. It wouldn't be a good idea to be caught watching them, after all. He was almost a hundred percent sure that James wouldn't remember anything of the night before, but it would be better not to tempt fate.

Regulus couldn't stop his lips tilting into a smirk, however, as the end of breakfast drew close. Sure enough, the curious burn of familiar eyes prickled over his skin.

Standing, he chanced a glance at the Gryffindor table to find James watching him, curiosity strong in pretty hazel eyes. The blush that spread over his cheeks when their eyes met made Regulus' mouth water.

Suddenly, being safe didn't seem like such a good idea.

Almost three weeks passed before Regulus broke. He'd been wandering, as he did most nights, when a familiar heartbeat filled his ears. He'd been avoiding the Astronomy Tower, but Potter was headboy and as such, Regulus always knew they'd cross paths eventually.

He was alone again, and Regulus couldn't force himself away from the deserted corridor they were now both occupying.

"Black? What are you doing out? It's way past curfew."

Regulus smirked, nodding his head in agreement. "I'm aware, Potter."

"Ten points from Slytherin then," Potter muttered, rolling his eyes. "Take yourself back to the dormitory, or I'll report you properly."

"I'm sure you don't want to do that," Regulus whispered, his voice seductive. "I'm sure you'd hate to get me in trouble, James."

"I, uh, what?"

"You're curious about me, Potter," Regulus replied. "You want to know what's going on with me… a shame that you've already worked it out and forgotten it."

James was frowning, and Regulus could practically hear his brain working as he tried to work out what Regulus was talking about.

"A shame that you're going to forget this time as well," Regulus added, as, in the same position as the first time, he sank his teeth into James' flesh and sucked.

A new pattern emerged.

Regulus would hold off for as long as he could, before temptation drew him in. He'd find James late at night, taunt him, seduce him, rile him, until he couldn't stop himself from taking the blood that ran through James' veins.

He never took too much, and he always sealed the wound with his venom, careful to make sure that James wouldn't remember anything of the encounters.

To his dismay, he soon realised that the times between his feeds were becoming shorter, the craving for the sweet-tasting liquid growing stronger with each passing one.

Fantasies of stealing James away, of hiding him somewhere safe, took over Regulus' mind. He wanted him, he craved him, more so than he'd ever wanted anything before in his life.

He fought to restrain himself when he saw Evans holding James hand, or kissing him before classes. He took his anger out on the trees in the forest when he couldn't hold it any longer.

Dumbledore was already watching him carefully, a suspicious glint in his eyes. Regulus wasn't sure what the old man knew, but he knew that he wasn't being as careful as he should. He simply couldn't stop himself from indulging anymore.

He didn't hide when he watched James in the mornings at breakfast, especially the mornings after an encounter. He didn't hide the smirks when, after five times, James began pushing Evans away. He didn't hide the satisfaction in his eyes when, eight times in, James refused to even talk to the redhead.

Regulus knew his venom had addictive qualities; he had read every book he could find about his kind to try and understand what he'd become.

He knew that, even though James didn't know what was going on, the Gryffindor was craving only Regulus' touch on his skin, that other people touching him would make his skin crawl. He knew that it wouldn't be long before James started losing concentration and interest in anything else.

He supposed he should feel guilty about that, but instead he was filled with a primal pleasure, because that meant James was his.

Meet me in the Shrieking Shack at midnight.

Regulus was admittedly stumped when the message appeared in his pocket. He knew it was from James, could smell his scent on the parchment, but he didn't understand why.

James didn't know of their late night meetings. He didn't know that Regulus was the cause of his decline in interest for others. Regulus was almost completely certain that James didn't remember anything of their 'relationship'.

Still, he was somewhat tickled that for the first time, James was the one with the surprise. Curiosity may have killed the kneazle, but satisfaction brought it back.

And Regulus was thirsty.

Regulus was waiting impatiently when he heard the muffled footsteps coming through the tunnel towards him. Lounging back onto a chair, he tapped his foot against the ground lightly. The whole house stank of werewolf, and it was clinging to the hairs in his nose in a way that Regulus knew would linger for days to come.

"Regulus?"

The word was a whisper, a beg and a plea all in one, and it took all of Regulus' self control to not answer. Instead, he waited until James pushed the door open, offering the black haired boy a wicked smile when their eyes met.

"Regulus," James murmured, again, stepping forward. "I… thank you for coming."

Regulus inclined his head. "I was curious."

"I… am I going mad? I've been having… dreams, maybe, I don't know, but I can't… I need…"

James broke off, shuffling forward until he was in touching distance of Regulus.

"Touch me, please… just a hand," he whispered, holding out his own hand for Regulus to take.

Raising his eyebrow, Regulus did as asked, brushing his fingertips over the tanned hand, lingering over the pulse point on James' wrist. He could feel the blood flow beneath his fingers.

All the tension in James' body fled, and he gasped out in relief.

"What… what's happening to me," he asked, his eyes pleading for answers. "I need you… I… I don't feel… comfortable without you… I don't… I"

"Shh," Regulus whispered, gripping James' wrist and pulling him down until he was seated on his lap. Regulus wrapped his arms around James, pressing their bodies closer as James' head fell back against his shoulder. "I've done you a disservice," Regulus admitted quietly. "I didn't realise that the addictive qualities of my venom would affect you so much."

"Venom?" James stuttered.

"Come now, you said you'd had dreams of me. You know what I am, even if you don't want to admit it to yourself."

"Why… what's going to happen to me?" James asked after a moment. His breathing was laboured, and Regulus took a moment to run his tongue down his neck.

"I could let you go back up to school," Regulus offered, though his hands tightened slightly to bely his words. "Or I could lock you up somewhere, just for me? Would you like that, James?"

A soft moan was all the answer he got, and he smiled to himself.

"Or I could drain you," he whispered. "Right where you sit now. You wouldn't even try to fight me, would you? You'd let me drink my fill, empty your veins. You wouldn't want me to stop."

Regulus could feel waves of arousal coming off James, and he knew if he looked, there would be a bulge where his jeans had fallen open.

Licking once more at James' neck, Regulus sunk his teeth in, drinking deeply. He could taste traces of his own venom, and he concentrated on those, pulling them out. When the blood ran clean, and James had stilled in Regulus' lap, he pulled away.

Taking his wand from his pocket, he healed the marks carefully, leaving no lasting imprint of his teeth, and picking James up effortlessly, he lay him out on the dusty old bed.

Pouring two blood replenishers down his throat, he waited patiently until James stirred on the bed.

"Regulus? What are we doing here?"

Reg smiled, flashing his elongated teeth. "Nothing for you to worry about, Potter. Obliviate."

Regulus avoided the Great Hall. He took the long way around to get to his classes and he forced himself to lay in his bed at night instead of seeking out the headboy. It was only two weeks until the end of the school year, and fighting himself, fighting his cravings, he'd made it.

He was still occasionally blindsided by visions of James, clinging to him helplessly, lost in his addiction to Regulus' venom, but he forced them away.

James was back to wooing Evans. He was back to playing pranks with his friends, and Regulus was sure, had passed his exams as expected.

It was hateful.

Even the briefest whiff of the Headboy brought about the most intense cravings Regulus had ever faced and he wanted him.

James was his.

Except he wasn't. And he never would be.