One thing that could be said about one Regulus Black in his first year at Hogwarts was that he was invisible to everybody. The other Slytherin first years had nothing to do with him; he was an outcast to them. The other Slytherin's ignored him, thinking him to be like his elder brother Sirius, a Gryffindor and a trouble maker. Sirius himself didn't acknowledge Regulus either, too busy plotting pranks with his best friends to notice his little brother and the teacher's expected him to live up to Sirius' standards from the moment he entered the class, not evening knowing many spells. It was hard for Regulus but he struggled through it and didn't complain once, crying silent tears in bed at night for fear he'd be ridiculed if he was caught sobbing over something his roommates saw as trivial.

But Regulus was wrong in one thing; Sirius did pay attention to him. Whenever they passed in the halls Sirius' grey tinted eyes would pass over his brother, concerned and try and scrutinised whether Regulus was harmed or not. When Regulus snuck out of the castle at night to take company in the silence of the forbidden forest Sirius would follow him at a distance and make sure no harm came to him. But Sirius was having issues with some of the other Gryffindor's about Reg, they threatened him and though he was not one to be easily threatened Sirius had held back for so long to approach his brother and he didn't know why but he still hesitated. As snow began to fall on Hogwarts' grounds Sirius, James, Peter and Remus were some of the first out into it but Regulus held back, watching them from afar like a strange reversal of their positions as other Slytherin's barged past him, laughing and again not noticing or acknowledging him.

Snowballs flew backwards and forwards across the grounds as Regulus darted between students completely involved in the games and did not notice a small black shape sliding effortlessly through them. Regulus breathed a sigh of relief when he made it past the large lawns of Hogwarts to the back of the castle where he huddled against the cold rock and watched his breath mist in the air. Screams reached his ears but Regulus went undisturbed and he felt tears welling in his eyes again. Having not allowed to have come home for the holidays Regulus knew he just had to endure it and soon it would get better or be over. Footsteps sounded behind him and Reg turned quickly, stumbling to his feet and drawing his wand but saw no one.

"I'm not in the mood for playing games. Just show yourself or leave." He said, sounding a lot braver than he felt. He was shocked however when Sirius gingerly came round the corner, hands raised in a peaceful sign and his eyes glued on Regulus' wand.

"You going to put that away bro?" He asked in a light, conversational tone. Regulus faultered before returning his wand to the inside of his robes. Sirius lowered his hands and came over to Regulus, leaning against the side of Hogwarts with him in silence. Regulus kept shooting furtive glances at his elder brother, arms crossed loosely, feeling extremely uncomfortable.

"Why are you here Sirius?" He finally spoke, his breath appearing in front of him as he spoke. Sirius smiled slightly and raised his hands again, breathing on them. They were red raw, from obviously manual labour making snowballs.

"I…well I've been watching you for a while and I wanted to make sure you were okay. I guess today I just had enough courage to approach you." The older Black explained slowly, choosing his words carefully encase it made him sound like a pervert. From Regulus' expression he had failed in that aspect.

"I'm fine I don't need you." He snapped. Sirius looked slightly taken aback.

"Okay sorry. I know the other Slytherin's have been giving you a hard time. Why not hang with me for a bit, just until you get onto better terms with them?" He put to Reg, placing his hands behind his head, looking so carefree as he exhaled tendrils of breath into the frosty, bitingly cold air. Regulus looked at him incredulous.

"The other Slytherin's hate you and you want me to hang with you to get onto a better footing with them?" He repeated.

"No not to get you onto a better footing with them, until you get on better terms. I don't like seeing you alone and stuff." Sirius mumbled, his head down eyes observing the footprints he and Reg had made in the fresh snow. Regulus followed his gaze, wondering himself.

"Sirius it's nice to offer and all but-."

"No wait I have an idea." Sirius said suddenly, turning to Regulus and smiling. "I have a perfect way for the Slytherin's to start liking you but you're going to have to play along. Here let me tell you my plan."

The next morning another blanket of snow rested on the ground as Sirius climbed out of bed and dressed with Remus, Peter and James. The other three were chattering about things that had happened the day before and what they were going to do today. Sirius however remained silent and when James turned to him and asked him if he was ready to go down to the Great Hall Sirius smiled, the plan was in action.

"Sorry guys I've got something planned already." He replied and left the dormitory to raised eyebrows and shouted questions as he hurried down the stairs and slipped out of the portrait hole. He made his way quickly through the corridors and down the staircases, darting between the students as they made their way to the Great Hall. When he reached the entrance hall Sirius made his way over to a side chamber and knocked once on the door. The door opened, revealing Regulus who came out and joined him.

"So do you have the food?" Reg asked as he straightened his robes.

"No but I know where the kitchen is." Sirius replied matter-of-factly and led his brother across the entrance hall to another side door as James, Peter, Remus, Lily and Snape arrived in the hall.

"Sirius!" James called but Sirius pushed Regulus through the door and made him walk down the long corridor.

"What if they follow us?" Reg asked.

"Then they do. Come on." Sirius laughed and led the way.

And so this was how it was for a week and a half. Sirius would go down to the entrance hall, meet Reg; they'd sneak to the kitchens, eat there and then spend the rest of the day together. James and Peter were suspicious of something only Remus seemed to have deduced what was going on. Sirius even snuck Regulus into their dorm some nights when the Slytherin's threatened him and Andromeda, in her seventh and final year, would allow Regulus to stay with her when Sirius could no longer sneak him in. Sirius had decided a week and a half should have been plenty of time and when he woke up on the Wednesday his plan was to unfold he sighed and smiled. What lengths I'm going to for him, he thought as he went about the normal day activities. Remus was the only other awake and he seemed to notice something was wrong with Sirius.

"What's going on?" He asked as Sirius made to leave.

"Nothing. Just make sure you're outside at some point today." Sirius replied and swept from the room. When he met Regulus the boy seemed extremely nervous, fingering his wand as he stood quietly waiting for his brother.

"Put it away Reg you don't need it yet. And remember the plan." Sirius whispered making Reg jump.

After they had eaten Sirius and Regulus made their way outside, the air was cold and crisp and the snow was fresh again. That was one of the things Sirius loved about Hogwarts, the snow never turned to and icy mush even after it had been trampled on over a thousand time by the students. Regulus led the way this time to the place they had picked out in advance and then they waited for other students to mill out onto the lawn. When Sirius spotted James, Remus, Peter and some of the Slytherin's they were hoping to impress sort of heading their way he turned to Regulus.

"Remember; don't be afraid to hurt me." He whispered. Regulus nodded, hand hidden but Sirius knew it to be clenched on the handle of his wand.

"Reg where you going?" Sirius asked loudly, loud enough to attract attention. Regulus started to walk off and Sirius caught his arm. Regulus drew his wand and before he knew it Sirius was flying backwards to land painfully in the snow.

"Don't touch me! I don't need you trying to protect me it's pathetic!" Regulus cried, raising his wand again. Sirius slowly drew his, giving Regulus time to disarm him and then advance on him menacingly. His friends had picked up speed, heading to help him so Sirius looked pleadingly almost at Regulus to hurry up.

"Reg I thought-."

"Thought what? That because I was hanging with you I actually spared you thought? That I was thankful for you stepping in and acting like a saviour to me? Think again Sirius I hate you." Regulus spat with such contempt Sirius was half convinced himself. Without warning another spell hit him and Sirius felt some of his ribs crack and a slash appear in his cheek.

"Reg…" He whispered, forcing himself to cry over the pain but made it look like he was crying over the fact Regulus had told him he hated him. Regulus raised his wand to deliver another blow when James barrelled into him and knocked him over. Teachers were running towards them as Remus helped Sirius stand and Peter brought him back his wand. Professor McGonagall and Slughorn took Regulus by an arm each and steered him away. Sirius knew the Slytherin's were laughing at him and that James and the others had a lot of questions but he himself smiled as Remus helped him hobble away, along with Professor. Flitwick.

"Take him to Madam Pomfrey boys." The tiny charms teacher squeaked, before hurrying away after McGonagall, Slughorn and Regulus. Remus and James both supported Sirius as Peter hurried ahead to warm Madam Pomfrey.

"Sirius what was that about? What have the past week and a half been about?" James asked. Sirius shook his head, hissing in pain.

"Let me get healed first James, then I'll explain." He whispered, limping slightly as they reached the hospital wing and Madam Pomfrey was fussing over him.

"Regulus what you did breaks school rules so you're going to have a detention, Professor. Slughorn will decide what you do and twenty points from Slytherin." McGonagall snapped. Regulus sat with his head bowed fighting tears. He hadn't meant to seriously hurt Sirius but it had been part of the plan.

"Yes Professor." He mumbled.

"Good, now get yourself off to your common room and stay there." McGonagall said as Slughorn moved over to the desk so they could discuss punishment for him. Regulus left sadly and made his way quietly to his common room. Upon entering however noise erupted and suddenly Slytherin's were patting his back and asking questions that all melded together, making them impossible to understand.

"One at a time." He managed to gasp as a Slytherin hugged him.

"You beat up Black. Seriously man I never thought I had it in you." One of Regulus' roommates said happily. Regulus tried to smile through it until the real testing question came.

"How come you spent a week or so hanging with him if you thought so lowly of him?" It came from Andromeda, who was one of the only ones who did not crowd around him happy at his display of violence towards Sirius. Regulus looked her straight in the eye and delivered the response he and Sirius had been practicing perfectly.

"I wanted to drive it in deeper. If he thought I liked him still then it would hurt more when I betrayed him then if I randomly came out with it." Andromeda smiled at the perfect performance and swept off to her dormitory, glad Sirius' plan had worked. Regulus felt wanted at last by the Slytherin's who had once ignored him. But he still remember to send a silent thanks to his brother who was lay healing in the hospital wing.

"So Sirius spill. What's been going on?" James asked quietly as Madam Pomfrey went back into her office, having fixed Sirius' broken bones and the stitching the cut on his cheek.

"I've been watching Regulus since he came into school. He's been lonely, invisible to everybody. I finally plucked up the courage to approach him and got an idea how I could get him to fit in with the Slytherin crowd, not that I want him too." Sirius replied gingerly sitting up.

"So you made him hurt you?" Remus asked, the only other to have caught on early to what Sirius was doing.

"Yeah. The Slytherin's hate us four don't they? Well I wasn't about to let him hurt you guys so I used myself instead. Made him hang with me for a while and then drive pain right into me. Telling me he hated me. It had to be a perfect performance and we pulled it off perfectly." Sirius continued, smiling at Remus who shook his head.

"What would you have done if he had seriously injured you?" James as incredulously.

"He doesn't hopefully know that many dangerous spells and it was all planned out, he wasn't going to. We started it when you guys and the Slytherin's were the perfect distance away and then started." Sirius replied softly, smiling reassuringly at James.

"So it was all an act and Regulus doesn't hate you?" Peter asked, just to make sure.

"Nope, it was all my perfect plan and if it worked the Slytherin's will be sucking up to him." Sirius said happily, glad it had all worked out.

"Wow Sirius you really care about him." James laughed.

"He's my brother, I sort of have to." He replied with a hearty smile as Madam Pomfrey came over and told them that it was time for them to leave as Sirius needed rest.

"See you tomorrow guys." Sirius called as they left before lying down into his pillows and sighing contently.

In the middle of the night footsteps disturbed Sirius' sleep and he slowly opened his eyes, shaking his head as he made out a figure sat by him. Grey eyes met blue ones as Sirius finally made out what the shape was and smiled at Regulus, who was rather flushed and looked slightly horrified at the sight of his brother in bandages and stitches.

"I'm sorry." He whispered.

"Don't worry about it. Did the plan work?" Sirius inquired quietly. Regulus nodded.

"Although I've got detention as well." He added. Sirius laughed lightly and patted Regulus' head.

"You're lucky they aren't writing to mum and dad. Did Andromeda say the line and did you give the practised reply?" Sirius asked, intrigued into how his plan had gone exactly as he had imagined.

"Yes and yes. Honestly you'll be brilliant at Divination it's like you can see the future already." Regulus commented, squeezing Sirius' hand.

"How do you feel?" Sirius smiled as Reg jumped when he placed his other hand over the hand Regulus was holding his with.

"I feel included and happy, but also sad because the only way that I would be included was to hurt you." The youngest Black replied slowly, meeting Sirius' eyes with tears brimming in his own.

"Hey don't cry. It's better than being invisible right?" Sirius asked. Regulus looked up at him shocked at how Sirius knew exactly how he felt.

"How did you-." He began.

"Know how you felt?" Sirius finished, Reg nodded, intrigued. "I felt like that too in my first year. Although I met James and made friends with him on the train I still felt invisible to everyone else and shunned because I was a Black. Then I made a great circle of friends and now I don't feel so invisible. But I'll tell you one thing." Sirius explained and Regulus nodded, eager to hear Sirius' apparently wise words.

"All the best wizards feel invisible when they first start Hogwarts. That's why they become great wizards, because they feel invisible and feel like they had to prove themselves. So you'll become a great wizard too one day Reg." Sirius said softly. Regulus almost burst into tears when he heard that and hugged Sirius tightly.

"I don't hate you Sirius and I never will. Ever."

When Madam Pomfrey came to check on Sirius the next morning she found Regulus curled up next to him and the boys hands joined together between them. Tutting she went about her morning business as the two Black brothers slept with a smile on their faces.

-27 years later-

Sirius opened his eyes to find himself lay on his side in his bed at Grimmauld Place and shivering as the covers had fallen from his thin, bony body. His hand was resting next to him, fingers curled as if he grasped something and Sirius immediately moved, remembering that day all too clearly. Not knowing that Regulus was one of the reasons why Voldemort was going to be brought down by Harry in two years and also not knowing he would never find that out since he would be dead by the end of the year by Hogwarts time Sirius found himself cursing the day he had ever come up with that plan. That had been one of many reasons Regulus had joined the Death Eaters. Sirius hated himself more now he knew that, because he had been so eager to see Regulus happy he had sacrificed the innocence of his little brother to the foul beasts.

Every night since that night Sirius had slept on his side with his hand curled next to him like it still held a ghostly version of Regulus' hand on that last night they had spent friends in Hogwarts castle, united as the two invisible brothers, who were soon to become equally famous, for entirely different reasons.