Chapter Text
Regulus can't do this. He's 20 years old, and a former Death Eater, and all alone, and he can't do this.
It was supposed to be Sirius in his place, because he's always been the good brother, the responsible one. Nobody would have pegged him as the latter, no, because once he got sorted into Gryffindor he had done his best to distance himself from pre-Hogwarts Sirius as much as possible - and that meant shunning the Black Family (10 year old Regulus included), running away from home at 15, hating anything remotely Dark, and being a reckless idiot.
But Regulus knows him. He knew his brother at 7 years old, he knows him at 20, he'll know him at 60. Even if he acted like a plebian around Potter, Pettigrew and Lupin, he'll always been a Pureblood Heir, and will continue to be one while he lives - no matter how much he might hate the traditions now. He would also never be a traitor.
If Regulus knows one thing, it's Sirius' loyalty (nevermind that his younger self would disagree; he was hurt when Sirius started spending less and less time with him at home during the summer holidays, when he ignored him at Hogwarts, when he ran away and never came back. But he is older now and understands that there is nothing Sirius could have done to help Regulus. Partly because he had no legal way to get him away from Grimmauld Place, partly because his younger self was already under Walburga's thumb by the time Sirius made his escape. Regulus can't fault his brother for getting away from that house). For that reason, he is certain his brother didn't betray the Potters.
Why would he? Regulus has first hand experience with Sirius' rants about his family's association with Death Eaters, with Him, and the Potters had been his way out. No, Regulus knows his brother; he wouldn't betray a friend, especially not the Potters.
But regardless of his certainty, there is nothing Regulus can do - at least not at the moment. He is a pardoned Death Eater, with no connections of value in the Ministry, and no way to convince anybody that his brother (the supposed right hand man of Him) is innocent. He'd probably only make it worse on himself if he were to start making noise around the Ministry about Sirius; it wouldn't surprise him if Crouch found a reason to chuck him in Azkaban too.
Regardless, as much as it pains him to think it, there are more pressing issues to deal with at the moment (and he is sure Sirius would agree), like kidnapping the Boy-Who-Lived and getting away with it, for example.
Regulus didn't mean to put himself in this position, but there is nothing for it now. It's not like he is going to let the poor baby live with those despicable Muggles. Who knows what the boy would grow up to be, if he even survives childhood with the way those relatives of his keep starving him, throwing him around, and generally being horrible human beings?
Regulus only meant to check up on the boy, because he knows he is his brother's godson, and if he ever sees Sirius again he wants to be able to look him in the eye and tell him he'd watched over the boy as much as possible.
He didn't mean to interfere in any way, at least not now when the boy wouldn't remember him and it would only serve to upset his relatives more. Maybe in a couple of years he could have dropped by every now and again in secret to teach the boy about their world and his role in it; with those Muggles as his family the child would surely grow up ignorant of his heritage and the Wizarding World's history, his place in it.
But he didn't expect to stumble across child abuse and child neglect. That, that wasn't part of the plan. So now it's all gone to hell, and Regulus is panicking because, as he's already said, he is only 20 years old, with a past that is hardly conducive to child rearing, and he wasn't meant to be the one to save and consequently raise the Boy-Who-Bloody-Lived.
He tries to get himself under control, swallowing a few mouthfuls of Calming Draught. It can't be helped; the boy can hardly be raised under such conditions, not to mention the shoddy state of those blood wards surrounding the house. Regulus is good with wards, would have gone on to become a Curse Breaker at Gringotts or something if it hadn't been for the war and almost dying to get one up over that genocidal maniac, so he knew what the wards were the second he Apparated near a dustbin at No. 6, Privet Drive. He overheard Dumbledore discussing the wards with McGonagall last week when he visited to express his thanks to the Headmaster for vouching for him at his Trial, but of course he hadn't understood what the words meant until now, after seeing the wards themselves.
Lily Potter gave her life to protect her son, and in what Regulus can only guess was a ritual of some kind, she cast a protective ward around the boy after her immediate death, thus ensuring he would survive a Killing Curse. It explains how the boy not only lived, but also vanquished the monster, however temporarily, and why he was left with a lightning shaped scar on his forehead - Sowilo is an important rune in most protection rituals.
The thing is, the ritual Lady Potter performed is meant to last only once - against one threat, and one threat only; one sacrifice in exchange for a one time protection. It appears, from what Regulus can piece together, that Dumbledore believes he can maintain said protection by having the boy live with his blood relatives (his aunt and cousin) for 10 consecutive years, enough for the protection to stay in place for the next seven when he will attend Hogwarts for most of the year.
Which isn't a bad idea, Regulus has to give it to him. In theory though. Because the reality is that no blood protection is worth child abuse, and from what he can see, the wards aren't even working properly, they're in shambles. If that is due to the Muggles' atrocious behavior or because the boy does not consider the place his home and his relatives family, Regulus can't exactly say.
The fact of the matter remains, though. He would have to get the boy away from here, and do it fast. Regulus doesn't know if there is anyone already watching the house on No. 4, although he doubts Dumbledore left the boy completely unattended with his relatives, but even if there isn't anyone, he can't take the chance of being spotted loitering around. His anonymity in this is paramount if he wants to get to keep the boy as well, and raise him.
So, with a deep breath to steel himself, Regulus puts up the hood of his dark cloak over his head, casts a Notice-Me-Not on his body, and makes his way over to No. 4. He has a baby to rescue.