He falls in love with Sirius as children, that first time they transformed together, with the wind blowing his shaggy hair around and his face screwed up in concentration and the faintest hints of black fur sprouting from his shoulders. And he knows, somewhere in the back of his mind where thoughts sometimes circle and prowl quietly until they decide he's ready to hear them, he knows that this is the way it will always be: he will always watch Sirius change for him, for them, and then too soon watch him change back. Sirius will never stay transfigured.

And he never does, and Remus cares desperately and couldn't give a flying fuck at the same time because it's worth it, almost all the time, for those moments when Sirius changes for him, for them, and is someone different. And sometimes it's minutes and sometimes it's hours and sometimes it's days, and for one perfect, breathtaking summer it was a season and Remus seriously considered dropping out of school and begging Sirius to just let him sleep in his bed for the rest of their lives because nothing he would ever do from that moment on would matter as much as that summer. But the time, however much it is, is worth the rest of it. Remus is fairly sure that he believes that.

And when Sirius Black…when he dies, Remus isn't surprised, not in the least, because who could have imagined Sirius as an old man? He could, of course, in his smallest tiniest most perfect dream where they are old men together pottering around the house and watching Harry's children play. But no one else, certainly not Sirius, who was probably surprised to have lived this long to begin with. And so when the arch swallowed him up, a wild laugh on his face, Remus felt something shatter within him. And when Harry broke down, Remus wanted desperately to commiserate, to tell him the truth, but some splinter of Sirius stopped him — I'm not gay, it's just sex, doesn't mean a goddamn thing — and he didn't. And he still didn't, when Dora started paying attention to him.

Remus isn't strictly gay, despite what Sirius told him over and over again. He's always been fairly equal-opportunity when it came to sex, not really preferring one set of genitals to another. The fact that the love of his life was a man was no more of a shock to him than the fact that the person he eventually married was a woman. More surprising was the way in which she seemed to hunger for him as he'd hungered for Sirius. Eventually he decided that he loved her back, mostly for her humor and life and energy and the way she smiled at everyone and gave endlessly of her love to anyone who needed it.

And so, once it happened, Remus tried to do better by her than he'd been done by. He tried to be attentive and kind and grateful and good to her. And most of the time it was good, lovely even, and then they were going to have a baby and she suggested Sirius as a name and he just. Ran away. Couldn't connect those two parts of his life. Went to Harry, begged for an escape. Got a lecture and a shaming instead, went back, told Dora that there was no way in hell he was naming a child Sirius, and they went on as before.

And then, when he saw Dora killed in the battle, when he threw himself into the fray, he wasn't sure who he was avenging. But it didn't really matter, did it, because whatever happened they'd all be dead, wouldn't they? And he'd see them again, maybe, if there was something after this. The last thoughts in Remus Lupin's mind as the life leached out of him were a picture: him and Sirius, arms around each others' waists, with Dora holding his free hand tightly; and the thought, That would be a nice way to pass eternity.