The Boy-Who-Lived-Next-Door
Contrary to popular belief, Voldemort wasn't an idiot. He wasn't insane either.
Well, he was a little bit so when he had been in wraith form, and when he had been brought back using Potter's blood. But that had been fixed easily enough when he realised he was far too weak and the fear that Wormtail had ruined the ritual somehow, making him weaker, had him making his way down the hill to the Gaunt shack to get the ring and merge with the horcrux within it. It had restored to him a vast deal of his power, his common sense and his charming good looks and he had realised how badly he'd fucked up his mission.
Honestly, he'd been an idiot, too worried that his more important, more pure in blood and consequently inbred, rabid, and insane Death Eaters wouldn't follow him unless he let them have their fill of bloodshed. He'd given in too much to their lunacy and more than anything else, this had been his downfall. He could see the way Lucius and Severus cowered in front of him, a pretence of course, but one still valid because they were still afraid of him.
When did he become Dumbledore? When did Voldemort first begin to require this obedience, this fear from his followers?
Oh, he'd always wanted it of course, but even at his worst he had known that it just wasn't feasible and had never needed it. The similarities between him and Dumbledore were far too many and it concerned him.
Merging with the ring horcrux though, it had made him a bit nervous. Were the rest of his soul phylacteries fine?
It would be a risk to go to Hogwarts to find the diadem, a risk he would take, but later, using Lucius' power as the head of the board of governors. Bellatrix would have to be broken out of Azkaban to check on the goblet, unfortunately, and the locket was in that cave far away.
The Diary was close by and so he demanded Lucius present it.
The anger when he found out Lucius had lost it, had him all but going insane again. He made his way into Lucius' mind to rip the information straight from the source, now untrusting of what the man would withhold.
It angered him beyond belief to know how his soul fragment had been destroyed. That it had been done by a fresh faced pre-teen was humiliating and yet…
And yet.
How fascinating that the boy should be a parselmouth. That he should face and kill the giant basilisk that even he had feared, back when he was still just Tom, that Potter should be bitten by the damn thing and yet survive, in the process finding Gryffindor's sword, an artefact Tom had coveted as a horcrux for ages.
But no matter how interesting, the events left him with a loose end. There was a giant hunk of his soul floating around in the aether as a spirit and he needed to anchor it to himself somehow.
There was only one way to regain a piece of soul lost in such a manner. Remorse, true remorse.
It would be difficult, painful. Remorse was something he had always struggled to feel, it was an anathema to him.
But then, once upon a time, failure was an anathema to him as well, and now...now it was so common, so well known to him, like eggs for breakfast.
Remorse, then.
A deep regret.
He regretted the entire Chamber of Secrets episode. It had resulted in Hogwarts being nearly shut down.
He regretted Myrtle's death. It had been accidental and meaningless, and the Warren line had been lost with her.
He regretted killing the Potters, all over a half heard prophecy.
He regretted breaking his word to Severus.
He regretted many things, but apparently it wasn't strong enough.
And Voldemort thought back to the night of the ritual, of Harry Potter, of the way he stood so tall, not unafraid, no, but more than willing to face him nonetheless.
He regretted more than anything else, underestimating Harry Potter.
His last regret does it, and he finds himself flooded with the memories of the Diary soul piece. Of the insipid conversations with the Weasley girl, her raptures over Harry Potter, of talking to the Boy-Who-Lived himself, of the obsession growing, of spelling his identity out on flaming letters, of feeling burnt inside out by the basilisk venom and yet in his last moments, his every sense focussing on the boy with the giant hole in his arm from a basilisk fang, the admiration he felt that even when Potter thought he was dying, he still had the presence of mind to take Tom down with him.
It was beautiful, that vindictiveness, parading itself as righteousness.
He needed to know more.
Finding the boy is easy, ridiculously so. Lucius, already desperate to gain his approval given the fiasco that was his attempt at keeping the diary safe, talks Fudge over and gets the address of Harry Potter's muggle home. With the diary piece assimilated, Voldemort is more Tom than ever and with a slight glamour, a little tweak of his nose, a darkening of his pale eyes, he is all but unrecognisable, albeit far more human than when he had been first brought back.
He doesn't know the place well enough to apparate to it and decides to use muggle means to get to the boy. It is a chore in itself to learn how the muggle world has changed but he does so out of necessity and is fascinated by how far they'd come. It drives him nearly to distraction but he learns and eventually he is on a bus out to Surrey to Number 4, Privet Drive.
What he finds is interesting to say the least. His nemesis lying on the patch of grass under a window in muggle clothes far too large on his tiny frame.
He didn't know much about current muggle trends but he still knew enough to know this was not normal behaviour. He put on the enchanted glasses and saw the boundaries of the wards, saw a pink haired chit hanging around the house under an invisibility cloak, watching the boy. He closed his eyes and reached out with his magic to find the wards offered him no resistance, as he suspected. He had used Potter's blood in the ritual after all, blood wards were unlikely to hold him back.
But then, Dumbledore was counting on his madness, on his ego, to keep Voldemort from coming down himself to face Potter. The wards would keep the Death Eaters away but he could so easily walk into Potter's house, slaughter his family before spiriting the boy away.
For a moment he wondered if that was exactly what he should do but…
Well, his biggest regret had been underestimating Potter. What better way to get a true idea of what the boy was capable of than to see the environment that created him.
He'd have to work out a good way to word it though. He didn't think his followers would be able to understand why he was moving into a muggle neighbourhood.