For Kelly, who requested RegSev.

For Camp Potter, event Fireworks (RegSev chosen from among other pairings), cabin Lestrange.

.

"May I ask something of you?" His voice is so damn small that you don't expect it to be Regulus when you turn around — somehow, despite their different Sortings, you would have expected Regulus Black to be like his brother, and you're all to used to hearing Black from all the way across the Great Hall.

"Not without cost," you reply honestly. He nods.

"How… how do you stop caring?"

"…you pretend not to long enough that the feelings cease."

"And that works?

You look at him curiously, but his face betrays no hint of why he asks. "Yes," you say very precisely. Regulus nods, and then he walks away.

And the expression on Black's face when his little brother gives him a cold look is— well, it makes you realise for the first time what sort of power you hold in your hands because he trusts you. Because he came to you.

.

"Regulus!" You can't help but use his first name, because Black will always be his brother.

He turns to look at you, seemingly surprised. You smile with your eyes and not your lips. He notices, but no one else does — no one else could, no one else is close enough.

You aren't sure he's going to smile back but then he does.

.

It absolutely infuriates Black that you have befriended his little brother. You didn't think it possible that the way he treated you could possibly get any worse, but it does — only when Regulus isn't around. When Regulus is at your side, Black behaves like a perfect angel. He doesn't want to alienate his brother.

But you watch as Regulus grows colder and colder toward his brother, impartiality turning into complete disdain, and you find it immensely satisfying to watch the pain flicker across Black's face every time Regulus brushes him off.

.

It isn't entirely about tormenting Black. You find, eventually, that you actually don't mind Regulus's company. He knows when to kiss up and when to shut up, and that's a good skill in an associate.

You don't have a lot of other friends — your housemates isolate you because no one is anywhere near self-sacrificing enough to risk the ire of Potter and co just for your company. But Regulus, Regulus walks beside you with impunity.

He's quiet, and he comes off as so goddamned innocent, but you find hidden depths to him — he is absolutely fiery when provoked.

You take to seeing how much provocation he can take without snapping, and you think that he begins to hate you until…

Until the day his brother tries to murder you.

You are livid, absolutely furious but Dumbledore has silenced you and you cannot tell Regulus why his brother is a monster.

He asks seven times if you are all right and you just want him to shut up, you just want his brother to hurt as much as humanly possibly — so you kiss Regulus fiercely.

You expect him to pull away, get angry. You expect it to drive a permanent wedge between the two of you — you want Black to feel guilty. You want him to know it is his fault that his little brother no longer has any friends, because the timing could not be a coincidence.

Instead, Regulus kisses you back just as fiercely, deepens the kiss, shoves you backwards onto your bed. Peppers kisses that turn to nibbles that turn to bruises on your throat and this is so much better, because this will hurt him so much worse. God, not only will you leave his little brother alone and friendless, first you will out him, turn him into as much of a pariah as you are — as you already are, so you don't give a damn about your reputation as it can't possibly get worse. Then you will break his fragile heart.

.

You very nearly go through with it.

.

You have plans — well laid plans — to out the both of you and make it seem like a complete accident. It is the first step to the end of it all.

But before you employ those plans you glance at him, you meet his eyes, and you can't.

He trusts you.

He trusts you absolutely and completely, in a way that no one has ever trusted you before. The feeling alone is a heady one; it makes you feel powerful.

But it also makes you feel responsible. This boy has entrusted into your care the most fragile part of him: his heart. He has pulled it out of his ribcaged safe-zone and placed it into your chest for safekeeping.

And you… cannot violate that.

Because somewhere along the line he became so much more than just a way to screw his brother — figuratively, that is. You're only literally screwing the one of them.

Somewhere along the line you began to care, however much you intended not to. You are a fool. You knew how much caring could cripple you and yet you let it happen all over again, you let another have the key to your heart.

At least this time, you know better than to let him walk away with it.