For the Serious Sirius Challenge by yellow14

Disclaimer: This story is based on characters and situations created and owned by JK Rowling, various publishers including but not limited to Bloomsbury Books, Scholastic Books and Raincoat Books, and Warner Bros., Inc. No money is being made and no copyright or trademark infringement is intended.

Warnings: Two swear words

~O~

Sirius stared at his wand in horror; he hadn't known that that particular spell could be used like that. He slowly looked over at Remus, lying on the ground, but staring right back at him; he imagined he could see the condemnation in the other man's eyes.

"Stop."

"Huh?"

"Stop thinking that."

"What am I thinking?"

"That I'm going to hate you for killing him. Sirius, look who it is, for God's sake! That's Fenrir Greyback! Did you honestly think that he was going to stop when you told him to? He was going to kill me!"

"Yes, but I killed him instead." Sirius started to hurl his wand away from him, as far away as he could get it, but a hand on his arm stopped him; he had forgotten just how fast Remus could move.

"Padfoot...he was going to kill me...and you stopped him. Yes, you ended up killing him, but that's not such a bad thing." Remus' soft voice penetrated the fog inside Sirius' mind, clearing away the sound of his mother's voice telling him that he was a disappointment, that he was a murderer. He blinked and then focused his gaze on his friend.

"Tell me how that's not a bad thing...I killed someone!"

"Fenrir Greyback was not a person, Sirius; he was a beast...a horrible, loathsome, terrifying beast. He preyed on innocent children, trying to kill them for the sheer pleasure he got from it; how do you think I got to be the way I am? I was six years old, Damnit! He preyed on CHILDREN! The only reason that I didn't die was because I'm a wizard." Remus shook Sirius slightly, trying to get his point across. "You didn't kill a man...you put a horrifying beast out of its misery!"

"But...I still killed something...I've never..."

"I know you haven't, but this doesn't make you any different than you were before. You're still Sirius Black, my best mate; you're not a different person just because you saved my life."

Sirius' eyes widened and he looked at Remus in wonder. "I did...didn't I? I k-killed him...but I also saved you, too...didn't I?"

Remus pulled Sirius in for a hug, sensing that his friend needed the close contact. "Yes, you did. You saved my life...and the lives of countless others. If you hadn't reacted how you did, who knows how many other people he would have gone on to kill? He wouldn't have stopped with me, you know that...right? You know he wouldn't have stopped with just me; he would have moved on to you and then on to someone else. He loved killing, Sirius. He's one of the main reasons that werewolves can't get regular employment...everyone thinks that we're all going to turn into raging beasts once a month."

Sirius felt reaction setting in and his knees buckled, sending both he and Remus to the ground; he could feel the sobs building within him and strove to control them. He failed miserably.

Remus felt his friend's shoulders shaking and shuffled around a bit before pulling a now openly sobbing Sirius into his lap and holding him as one would a child. Sirius buried his face in Remus' shoulder and wrapped his arms around him, clinging to Remus for all he was worth. Remus began to rock back and forth slightly, remembering his mother doing much the same for him when he was small.

Neither one knew how long they sat there, on the forest floor, before Sirius' sobs quieted down and he gained control of himself. He relaxed into Remus' hold and tried to gather his thoughts. "How are we going to explain this to the Aurors?"

Remus thought for a minute before coming up with an answer. "Moody."

"Mad-Eye Moody? You don't think he'll take me in for this?"

Remus shook his head. "He's been trying to find Greyback for months; why do you think we were out here? I've been helping him look."

"You're helping the Aurors?" Sirius wasn't sure if he could be more shocked than he was. "Mad-Eye Moody asked for the help of a twenty year old?"

Remus chuckled slightly. "Yes, he asked for my help. How many other werewolves do you think would be alright with hunting down another werewolf? He knows that I hated Greyback for what he did to me."

The two men stood and looked over at the body of the werewolf. Neither of them knew exactly what to do with it; it was kind of obvious, from the rather large rock that rested on his head, how Greyback had died.

Sirius finally got his brain back in working order. "I'll go for Moody; you stay here with that."

"Alright...but before you go...I have just one question."

"What?"

"When you cast that spell, did you realise that Wingardium Leviosa could be used like that?"

Sirius shook his head. "Hell no! I never thought that I would be able to lift a boulder with it, let alone let it go when I wanted to."

Remus chuckled again. "Go get Mad-Eye." Sirius gave him another hug before disapparating. Remus looked down at the body of his werewolf sire. "I'm glad it was him, and not me, that killed you, you filthy piece of shit. I'm not sure I could live with myself if I'd had to do something like that; thankfully Sirius realises that he saved my life when he took yours. I'd say we're even now...you made me a werewolf to punish my father and my best friend killed you to save me. I've still never done a thing to you."

Remus leaned against a tree and waited; less than five minutes later, he heard multiple cracks of apparation and knew that Sirius had returned with Mad-Eye. He couldn't wait to see the Auror's face when he heard that Fenrir Greyback had been felled by a first-year's spell...he grinned in anticipation.