Harry Potter: Raised by Wolves.

"How is that possible?" Harry croaked, eyes wide.

"When an ancient family line dies out, or the last remaining heir becomes ineligible to hold the position, heirship can be transferred in multiple ways. In this case, when you defeated the Dark Lord Voldemort — believed to be the previous blood heir to the Slytherin line — you ended the line, and the magic deemed you a suitable replacement. You must share blood somewhere with Salazar Slytherin, but within pureblood families that isn't uncommon. The Slytherin family magic is unique, in that it has certain requirements for an heir less about bloodlines, and more about magical strength and purity. The Dark Lord, when he entered this bank as a youth and took a line test, was an ineligible heir for the Slytherin line. No doubt his core was already tainted with too much dark magic for the family magics to accept him."

"But wasn't Salazar Slytherin a dark wizard?" Confusion was plain in Harry's voice, and Gorrak chuckled roughly.

"Your wizarding history books aren't quite as accurate as your people believe, Mr Potter," he remarked. "Salazar Slytherin was no true dark wizard. His father, Septimus, was. We believe that Salazar himself changed the conditions of inheritance in the face of his father's twisted magical core. The practice of what most wizards now consider to be dark magic was, back then, fairly neutral casting. Instead, it refers to what you now see as the blackest arts. The Dark Lord must have started some truly awful things at a very young age to have rendered his core ineligible."

Opening his mouth, Harry almost asked why they didn't just tell the wizards the truth, if they knew the real history of Salazar Slytherin. Then he thought about the attitude most wizards had towards goblins and other creatures, and his jaw clicked shut. No one would believe them if they tried. "So what does all this mean for me? Being heir to all these houses?"

"At present, not as much," Gorrak explained. "You will be unable to take on your full responsibilities until you are of age. However, heirs to ancient bloodlines play an important role in wizarding culture — you are the future of your people, Mr Potter. It is your job to preserve and uphold your family magics, as well as prepare yourself to enter the Wizengamot when the appropriate time arrives. I suggest you contact other family heirs and discuss the role with them; I'm afraid goblins know little in the ways of wizard culture." He leaned back in his chair. "The confirmation through the Line Test will also allow you access to any vaults under the names of these families, though I'm afraid due to your age you cannot access many of them without a guardian. I can have a portfolio assembled of your vaults and properties and sent to you within the week."

"If I may, Mr Potter," Farlig cut in. "It may also benefit you to research independently what it means to be the heir to houses as old as yours. There are no doubt many books on the subject. Of course, you can always choose to reject your Wizengamot seats and any adjacent responsibilities, but they would continue to be held by your proxy. I believe that is currently Headmaster Dumbledore."

At the thought of Dumbledore being responsible for his family name, something inside Harry hardened. "No," he said immediately. "I'll take my place. I'll learn." He didn't entirely know what all this entailed yet, but he knew one thing for sure — he didn't want Dumbledore making decisions on his behalf. Not now, and not when he was seventeen.

"Excellent choice, Mr Potter," Farlig murmured approvingly. "Should the goblins of Gringotts be able to assist, please do contact us."

"You've already done more than I ever expected," Harry replied, head still spinning with everything he'd learned. "I— how much do I owe you, for all this?" It occurred to him belatedly that the gold-driven species were unlikely to do such a kindness for free. Farlig and Gorrak shared a smirk. "We will take the necessary expenses from your vault and owl you the bill, Mr Potter," Gorrak informed him. "I shall send it alongside your portfolio. I will also send recommendations for an account manager, and perhaps some investments if that is your wish. The money in those vaults has languished since the fall of the Dark Lord Voldemort, if not longer — seeing it back in circulation would make goblin-kind very happy indeed."

If there was one thing Harry had learned from being forced to live with Vernon Dursley, it was that investing money in the right things was very important. "I would appreciate that, Gorrak. Thank you."

"It is our pleasure, Mr Potter. Now," Farlig said, clasping his hands in front of him. "I believe you originally came here to withdraw money from your vault?"

Harry left Gringotts with his purse weighed down with gold, and his head weighed down with thoughts. He glanced at his watch, and his eyebrows rose he'd only been in there for a little over an hour. It felt like a lifetime, it had changed so much.

Buying the wand holster was now the last thing on his mind. Instead, Harry made straight for Flourish and Blotts. He'd already spent half a day wandering the shelves, learning the many varieties of books available inside — no longer just going straight to the shelf for Hogwarts students and never venturing further. Familiar with the shop's layout, Harry found his way to the shelves full of books on wizarding history and culture.

A smirk tugged at his lips as he thought about what Hermione might say if she saw him buying books of his own free will. That smirk faded, however, when he thought of Ron's expression at the sight of the books themselves — titles like 'The History of the Wizengamot' and 'Inheritance Magic Explained'.

His eyes scanned the shelves, looking at the other people in there purchasing books. Perhaps it wasn't the best idea for Harry Potter to be seen buying books about pureblood culture.

Harry was about to start putting the books away, when his gaze caught on the bright paper of the bag from Gambol and Japes — of course! He'd almost forgotten about his purchases there, he'd had so much on his mind since then. He rifled through the bag until he found what he was looking for; small, egg-like capsules that promised a cunning disguise for up to thirty minutes. Supposed to be used to avoid being caught setting a prank, but Harry had bought some for the days when he wanted to go outside without being Harry Potter, with all that entailed.

He hid behind a deserted shelf and split one of the capsules over his head, feeling the magic run down him as if he had indeed just cracked an egg in his hair. Glancing at himself in the window, he grinned; staring back was a pale boy with straw-blond hair and dark brown eyes, his square face nothing like Harry's own. A shift of his fringe made him grimace when he saw his scar was still there, but luckily the disguise's hair was long enough to cover it. It would be enough.

Now on a time limit, Harry raced through the bookshop, tossing titles into his basket whenever they appealed to him. He didn't want to look too suspicious by just getting a stack of books about purebloods, so he threw in a few more that looked interesting — a book of defensive charms and wards, one titled 'A Hundred Spells Every Wizard Should Know', a small book called 'A Muggleborn's Guide to the Wizarding World', and one on goblin culture. It looked like he'd found some valuable allies, after all, and he wanted to learn more about them. Satisfied, he took his heavy basket up to the register, handing over the gold with a smile and adding the large bag of books to his other purchases.