The first note, he had found on his study desk. It was the summer holidays, and he was back at home, exchanging Hogwart's airy but bustling corridors with the eerily still and sweltering corridors of Grimmauld Place.
He had awoken to the familiar darkness that permeated his room, with just a sliver of sunlight that had filtered in through the tiny gap between the heavy, velvet drapes that covered the large, French-styled windows. The usual shadows warped the corners and took on strange shapes, distorting the original item and blurring the fine line between reality and dream. It was a problem that he often had.
Therefore, after kick off the stifling sheets and padding towards his table, he had frozen in shock upon seeing a note on his table. Being an very organised person, he always made sure that all his papers were kept away neatly so that he would never have any troubles looking for them. It was thus, to his utmost shock, to see a slip of parchment on his table, clearly torn from a roll of parchment that was similar to his own, judging by the shade of the parchment. Even more puzzling was that all his parchment and papers were still in order, so no one had torn it off from his roll. It was a rather unique shade, creamy but aged; not only was the original colour mostly favoured by his family, but the parchment only took on such a hue from being stored in one of the basement cellars.
Unnerved by this train of thought, he shrugged it off and instead opted to grab his wand and cast as many detection spells as his sleep-addled mind could conjure up. Satisfied that it probably wasn't charmed to bite off his head or rot off his arm, he carefully reached for the small slip of parchment, tilting his head sideways as he considered the writing on the paper. It looked as though it was printed in perfect copperplate; that didn't tell him much, since most purebloods wrote like that. But the impatience and slightly slanted writing was telling; not many purebloods wrote so sloppily. Either the person was in a rush, or… "Damn you, Sirius Black." Even after his brother had left the house, his presence still haunted it, like a person's shadow; something that one could not shake off.
Flipping over the parchment, he took in the strange, cryptic words, feeling the air rush out of his chest as though he'd been socked in the stomach.
"Why did you do it?"
In truth it could probably have referred to anything, from why did he start with his Astronomy homework to why he had poured pumpkin juice down one of his housemate's back as revenge for snapping his quill, but when his eyes recognised the letters and formed them into words, there was only one person's voice he heard. Rough and raw, tinted with a vindictive accusation, haunting the crevices of his mind just as it haunted the house.
Sirius had said the same words to him, over and over again, asking him why; why was he a Slytherin? Why did he hang out with the people he had chosen? Why did he read all those books? And worst of all, why are you a filthy little Death Eater?
"I just am, brother," Regulus spat angrily, crumpling the piece of parchment in his hand, furious at himself for being defeated by a mere memory of a boy who hated him. He should have been worried about how the person had breached the wards, both the ones around the property and the one around his room, but instead, that train of thought, like all the rest, merely returned to confirming that it was, in fact, his brother who had left the note, back here to haunt him and remind him of his guilt, of his regrets, to torment him till the end of his days for a choice that hadn't even been entirely his own.
The next morning, he found himself once again, blinking into the faint light of dawn and the sultry heat of summer, wondering whether he was still dreaming, if it was perhaps his own conscience that was punishing him for all of his cruelties, as he stared down at a nigh identical piece of parchment, fresh and smooth, with the ink barely even dry, but the same words dancing on the page.
Why did you do it?
Tearing it to shreds did little to calm his shaking hands,
For the rest of the day, as he walked around the house, doing as much as he could to keep his mind off the note, feeling his skin itch with the echo of his brother that the note had brought back, expecting to see fiery grey eyes and a disgusted expression at every corner that he turned, expecting to hear rows and the crashing of china, and instead be met by a heavy, oppressive silence.
It was a heavy burden to bear, and one that he soon learnt that he had had to bear for a long time indeed. It's been weeks as the notes kept appearing, each like the others; always the same writing, always the same parchment, always the same barely dried ink and fresh parchment.
Always the same accusing eyes and achingly familiar face, boring into his wretched soul.
It was as though the note had resurrected Sirius' presence, forcing each and every derisive word that had been uttered to brand themselves into his mind's eye, and above it all, the same accusing question, evoking simultaneously an abated fury and an empty, hollow feeling in his heart, hammering itself into his brain.
In the inexorable darkness of his room, there was nothing but him and the same words, his heart suddenly too heavy for his frame.
Why did you do it?
Why did you do it?
Why did you do it why did you do it why why why?
"I DON'T KNOW!" Regulus screamed desperately at his wall as he slumped against the grey silk, sobbing miserably as his brother's word burnt through his mind, reminding him again and again of his foolish choices, of his helplessness, of the lives he had ruined, both the innocents' and his own.
Alone in a dark room with walls filled with tattered newspaper clippings of his side in the war, glorifying the atrocities of a conflict beyond his grasp, a boy kneeled down in front of his bed and cried bitterly for the things that he should have done and didn't, and the things he shouldn't, but did.