A/N: Ok, I swore I'd never do this. Never write Harry Potter fic. But then I read the Shoebox Project. Which every Potter fan must read right now. So this is set more or less in Shoebox-verse i.e. Marauders era. So my first shot at this. Enjoy!
While it was James who first voiced the thought of what might be wrong with their friend, it was Sirius who confronted Remus about it. It had taken both James and Sirius to be sure of their conclusion and James had been all for both going to him at once, but Sirius had stopped him, saying that they should do it gently, lest Remus think they were angry with him. James had agreed and so Sirius had gone alone up to their dormitory to talk to their friend.
"Remus, mate?" asked Sirius asked tapping on the dormitory door.
"Yes?"
Sirius pushed the door open slowly and peered inside.
Remus was sitting on his bed, a large book open on his lap as usual. He was looking up expectantly at Sirius, a pleasant expression on his face. He clearly had no idea that Sirius and James knew.
Sirius entered the dormitory and, after insuring it was empty save for himself and Remus, tapped the door with wand, locking it.
Remus frowned.
"Don't want to be interrupted, um overheard," he corrected himself quickly, realizing how awkward it had sounded.
"What is it?" asked Remus, setting his book aside and sitting up more attentively.
"I just wanted to, um, talk, you know."
"What about?"
Sirius bit his lip and looked, to Remus, very un-Sirius-y. Sirius was usually so full to bursting with confidence that it was almost disgusting, but now he seemed hesitant, unsure, even scared.
"What's wrong?" asked Remus.
Sirius shook his head and crossed the dormitory to his friend's bed. He sat down on the edge and shot a sideways glance at Remus, who frowned and swung his legs around to sit next to Sirius.
"Look, Remus. James wanted me to-. That is, I thought it was a good idea if-. We've been talking and we think that-. Damnit."
"What?" asked Remus again though his previously concerned voice was now laced with fear. No one seemed to dying. He'd know if someone was dying, right? But something was most definitely wrong. Sirius and James couldn't know, could they?
Sirius looked away, positively radiating discomfort.
"I know, Remus," he said at last.
"Know what?" the other boy asked slowly, feeling terror explode inside him as he braced himself for the moment when the fragile life he'd built at Hogwarts came crashing down around him.
"What- where you go every month. Well, not where so much as why."
For a fleeting moment Remus considered denying the whole thing, but he couldn't lie to Sirius, not now.
Remus sighed and looked away.
"I guess that's it then," he said quietly.
"What?" asked Sirus, completely thrown off.
"You're here to tell me that you don't want anything to do with me, that you can't believe I lied to you, that I shouldn't even be at school. That I'm a-."
The unspoken work monster hung horribly in the air between them.
Sirius stared at him, shocked.
"It's Okay. I get it. I'll leave you lot alone."
"Remus," said Sirius quietly.
"It's Okay," Remus said again. "I understand." It hurt worse than it had the one other time this had happened, but at least he knew what to expect.
"We don't want-, any of that," said Sirius slowly.
"I— what?"
"I'm not asking you to leave, mate. We just wanted to know that you didn't have to keep trying to hide it."
Remus stared at him blankly, his brain refusing to comprehend what Sirius had said.
"What?" he said again at length.
"It's Okay," said Sirius.
Remus shook his head.
"But you know that I'm- that I'm a- a-?"
"Werewolf?" suggested Sirius helpfully. "Yeah."
Remus made desperate flapping motions with his hands.
"It's Okay, no one can hear us here."
"So you and James know?"
"Yeah."
"No one else?"
"No. Unless you've told anyone."
"Dumbledore knows."
"We figured."
"You're- you're alright with it?" asked Remus tentatively. It was far to good to be true.
"Yeah. I mean, I can't say we're keen on you lying, but it's not like you'd introduce yourself "Hello, Remus Lupin. I'm a werewolf. Nice to meet you"" He laughed.
"Some people think I should," Remus replied darkly.
Sirius frowned.
"Werewolf registration."
"They do that?"
"The Ministry keeps tags on us, yes."
"What? Like Magical Law Enforcement?" Sirius asked uncertainly.
"Department for the Regulation and Control of Magical Creatures," Remus corrected him in a flat recitation.
"That's not on," said Sirius at once.
"What? You don't think the Ministry should know who's likely to start biting people?"
"Well, I dunno. But Control of Magical Creatures? It's not like you're not human."
"Most people would argue with you on that one," said Remus coolly.
"Not on," said Sirius again.
Remus smiled somewhat weakly.
"I suppose people aren't perfect."
"I suppose not."
A silence fell between them for a few moments.
"You're really alright with it?" asked Remus.
"Yes," Sirius replied, starting to sound slightly frustrated. "You don't have to sound so damnned surprised."
Remus chucked darkly.
"What?"
"Nothing."
"No, you're thinking about something up there." He tapped the side of Remus' head. "What is it?"
"Nothing."
"No, tell me."
"Sirius."
"Tell."
"Fine," Remus sighed. It was so much easier not to fight Sirius about these sorts of things.
"Just someone else found out once. Or guessed close enough and I told them. I was pretty young. And, well, it didn't end well."
"They aren't here, are they?" asked Sirius.
"No."
"It was a muggle?" he gasped.
"No. Her family moved to France. I think she's at Beauxbatons now."
"Oh." He was silent for a moment.
"You're sure that it's alright?" Remus asked.
"What? Of course. Mate, we need to work on your self-confidence." Sirius smiled.
"There are people who think I should been killed the next morning."
Sirius' face twitched and Remus could scene his protective nature coming to the front.
"I was six years old, Sirius, and who knows how many people think I should have put down like the animal they see me as. Probably more think that than not."
Sirius let out a soft sound that was part shock, part pity, and part something else. Was it awe? Awe that such a small child be become such a terrifying dark creature.
"It's Okay. You're still our Remus."
Sirius' smile was so real and so genuine that even shabbily-dressed, chocolate-eating, hiding-behind-books, resistant-to-human-interaction Remus wanted to bask in its warmth forever and for the first time in his life he knew he could look at someone and truly call them his friend. He smiled back and it felt right.
"So," said Sirius bouncing off the bed, all light heart and Boy's Club energy. "Dinner?"
"Sounds good," said Remus, putting his book away and following his friend down towards the Great Hall.