AN: Just a quick note, I haven't decided on any ships yet so feel free to make any suggestions you want, and I'll consider them, though obviously for certain characters they won't happen for a while.
Remus Lupin knew he was probably making a mistake, knew seeing the boy would probably just cause him more pain in the long run. But, well, he wanted to know that his best friends son was okay. It had been five years, it had taken him some time to figure out where Dumbledore had left him, and all he wanted was just one quick glimpse of the little boy he'd loved as much as he would his own child. He paused outside of the house, staying out of sight from the windows and frowning slightly when he heard shouting from inside. Loud shouting, though he couldn't quite make out the words, and a pained noise too, he noticed one of the neighbours, who was putting his bins out, glance at the house and roll his eyes.
Remus was about to walk up to the door and knock when it was thrown open and he quickly hid, watching as a tiny boy, smaller than any six year old rightly should be, came rushing out, and even in the dark he could see the black hair and green eyes that Lily has decided to settle on when James had quietly told her that he wanted to cast the binding spell on Harry's Metamorphagus abilities until he was old enough to control them. And he watched with a horrified look on his face when the little boy stumbled and practically did a flip in his haste to get out, trying to catch himself and crying out in pain as a voice bellowed "If you're going to be ungrateful you can freeze you damn freak." before the door slammed shut and there was an almost terrifying silence as the man who'd been taking the bins out glanced pityingly at the boy and headed inside.
After a moment, when he was certain no one else was going to bother Remus stepped into sight, forcing back the pain he felt when the tiny boy looked up and flinched away at the sight of the stranger. His face was bruised, older bruises from the look of it. He tensed up slightly but he kept his face gentle. "Hello there... are you okay Harry?"
"Y-you know my name?"
"Of course I do." Remus gave a small smile, ignoring the fact that he was well aware how angry Dumbledore would be if he knew that he was doing this, "I was a friend of your daddy."
"You were?" the boy's eyes widened, and though he was still clutching his arm he no longer looked like he was about to burst into tears. "Are you here to rescue me?"
"Rescue you?"
"From the Dursley's... they're really mean and they hurt me and... and no one ever listens to me and I hate them!"
Remus felt his blood turn to ice. He shouldn't feel surprised after what he just witnessed, seeing those bruises, "They hurt you?" at the boys nod he felt a surge of anger towards Dumbledore.
The old man had swore to him that Harry would be safe, that he'd be safe and happy and yet here the boy was covered in bruises and hurt left outside in the cold. Before he even thought through what he was doing Remus shrugged off his jacket and draped it over Harry's shoulders, "Yes, yes I'm going to rescue you." he'd deal with the consequences later. He couldn't leave Harry here, not after seeing this. He'd take him home, to the place he'd brought himself after that fateful Halloween, with some of the money James had left him. It was in the middle of nowhere, so he wouldn't be a threat to anyone when he did transform, he'd have to find a way around that of course, but he'd find a way, he was sure. Of course he wouldn't be able to do this legally, being a werewolf, but, well, his friends had broken laws for him, and really, kidnapping Harry might break the law, but who would know it was him who did it? As long as he was smart no one would ever know and Harry would be perfectly safe.
With that thought in mind, and seeing the way Harry's face lit up, the way he was so willing to trust a complete stranger if it got him away from the Dursley's, he picked him up, careful not to hurt his arm anymore than it already was, unable to help the small smile he gave when Harry let his head rest of Remus' shoulder. Once the boy was asleep he would Apparate them home.
So he walked for long enough that Harry's breathing evened out and he felt all of the tension leech out of his body before he apparated them home, carefully laying Harry down in his bed, frowning at the state of his clothes before kissing his forehead and tucking the blankets around him, thinking for a moment before he removed the spell that blocked his Metamorphagus abilities and got to work preparing things. He could sleep in the chair in his room for tonight, he'd deal with sorting out the spare room, which he'd been so very certain he'd never use, in the morning. And he could shrink some of his clothes down until he got to go shopping with him. With that thought he quickly grabbed his spare blankets and wrapped them around himself, sitting in his chair and closing his eyes.
Perhaps he was being ridiculously reckless. But he was certain that it would all seem better in the morning. He just had to get some sleep, and then he could deal with the situation.