Timeline:
Begins: After the Battle of Hogwarts.
Ends: Future.

Alterations from Canon:
During the Battle of the Astronomy Tower Harry defeats Malfoy and wins the allegiance of the Elder Wand which bonds to Harry when he arrives at Dumbledore's corpse beneath the Tower.

Ron has his tantrum and leaves during the Horcrux hunt, Hermione throws herself at Harry for comfort and Harry finds himself without a reason to deny her. In the aftermath they are both a lot happier and they continue their new relationship.

After rescuing Luna and Ollivander from Malfoy Manor the couple end up at Shell Cottage. Luna identifies the Elder Wand. It's a short deduction from there to the Cloak and under Bill and Fleur's cursebreaking the snitch opens to reveal the Stone.

As Master of Death Harry compels the shade of Albus Dumbledore to cough up the truth and with the power of the Hallows Harry is able to purge himself of the soul fragment in his scar.

Also Dobby lives, because why not?

Pairings:
Harry/Hermione.
Harry/Pansy/Susan/Daphne.
Harry/Padma/Luna.
Harry/Multi/Harem.

Story:
In battle against Voldemort Harry uses his power as Master of Death to tear Riddle's mutilated soul from his homunculus body and binds the Dark Lord to his will. He pronounces the Rite of Conquest and declares the subjugation of House Gaunt, all its soldier, its retainers and its servants by House Peverell.

With control of Tom's magic, for the short while he holds the shade to the mortal plane, he seizes control over the Dark Mark of every Death Eater and subdues each one by tearing their magic from them as well, causing them to collapse unconscious, reduced to squibs and effectively ending the war.

The members of the DA are assigned different responsibilities to clean up, treat wounded, survey the castle and so on while Harry finds himself besieged by people who see him as the next Dumbledore. If they aren't afraid or resentful of him then they are worshipful and want him to tell them what to do. When after a week Kingsley finally puts together some semblance of a Ministry and starts taking over the clean up Harry and Hermione leave.

Asking Dobby if he and other Hogwarts elves can 'gather all our stuff' and 'take it home' they are surprised when they arrive at Grimmauld Place to find it stripped bare. Querying Dobby results in them being apparated across the country by the little elf, coming to stand before a large and ancient looking fortress. Welcome to Castle Peverell, Lord Harry James Potter-Peverell.

The fortress is crammed full of a truly preposterous quantity of sculptures, tapestries, paintings, every kind of furniture, stacks of wine bottles, mountains of dishware, an actual sailing boat and other ridiculous things. Harry did say 'all our stuff'. In perhaps the only room not cluttered with this debris they find a suitable bed along with their trunks and spend the night together with the first privacy they've had since before the battle.

In the morning however they find the castle crawling with elves. Where did they all come from? From the Avery, Nott, Bulstrode, Parkinson, Goyle, Malfoy, Jugson, Carrow and other Death Eater families. Just like all the stuff in the Castle... war booty seized by conquest. What about the families? Oh, those are here too! A dungeon filled with screaming and crying purebloods. Silencing them so he can think Harry can only get 'They belong to Master Harry' out of the elves.

The Dark Mark was little more than a modified slave brand and every Death Eater who accepted it made themselves the indentured chattel of House Gaunt... and thus House Peverell. In fact wherever the Marked follower was the Head of House or the acknowledged Heir of a family they also gave their entire family to the Dark Lord as chattel, making them too Harry's property now.

A meek Pansy Parkinson clothed only in a poorly concealing lace slip comes to the front of one of the cells and Harry drops the silencing charm on her. She timidly asks what he is going to do with them. After much hair-tearing and heapings of resignation Harry learns that, like Pansy, most don't want to be freed... because as he is now Head of House for all these families to be freed would mean disowning, disinheriting and dishonouring said person. They'd be homeless, penniless and nameless - the last possibly being the worst for a pureblood.

Being his chattel Harry orders each and every one of them to be truthful in answering his questions and soon he has a few dozen less slaves to worry about as they confess their crimes and actions in support of the Dark Lord and get shipped off to the Ministry. The remainder he gives orders not to leave the Castle grounds, not to harm each other or either himself or Hermione and everything else he can think of during the moment. Then they are released.

Pansy starts following them around and admits she doesn't really have any idea what else to do. Hermione stumbles upon the library and almost orgasms on the spot. A collection of the libraries of Peverell, Black and Potter families along with all of the books from every Death Eater family. It's a chaotic mess though, just dumped by the elves. Harry says maybe somewhere in it all is a way out of this mess he has found himself in.

As Hermione starts browsing and sorting the books a quick discovery is made, Pansy can't see any of their contents. It's probably family magic, she tells them, confining access to the books to only bloodline members of the Peverell family acknowledged by the Head of House. Why can Hermione see them then? Pansy smirks and hazards a guess that she has enough of Harry's magic in her by sexual relations that the library spells see her as Harry's consort or concubine.

Harry finds himself stuck in the same position he just escaped, organising and settling disputes and problems amongst all his new slaves. Hermione starts digging though the library with Pansy but Hermione needs to read out anything relevent since Pansy can't see a word in any of the books. 'Unless you want me to sexually pleasure Harry? Guess you keep reading then'.

Letters start arriving from all sorts of people but of most important note are the ones from Kingsley informing him that as their owner he'll have to be present to give consent to the administration of Veritaserum for all the guilty slaves he turned over as well as from members of the DA who have information for him or just want to see him.

Elves have soon brought Dean, Neville, Susan, Padma and surprisingly Daphne Greengrass. Daphne is looking for her younger sister Astoria who is, of course, amongst Harry's new slaves. Not because the Greengrasses were Death Eaters or that Astoria was but because of Astoria's marriage contract to Draco Malfoy, extorted from their father by Lucius. Only Daphne and Susan have an ideas about what laws and magic apply to Harry's control over his slaves or how to free them and they can't read the library either.

In one of the books Hermione finds the outlines, rules and language of a Concubinage Contract and after mulling it over tells Pansy, Susan and Daphne about the details... and asks them if they are interested. Temporary agreements that add them to the Peverell household only as long as they continue to 'provide service' for the Head of House. Service in fact being sexual pleasure. As little as a handjob would suffice but would probably not give them access to the library for very long, the more intimate the act the more of Harry's magic they would have on and in them and the longer the spells of the library would recognise them as members of House Peverell.

Pansy is surprising the most open to the idea... and admits that during Hogwarts she used to watch Harry and Hermione and wish that Draco treated her with even half the kindness and friendship Harry treated his friends. She used to imagine being in Hermione's place and when it came to sexual fantasies, well Draco didn't really scratch that itch so well. Susan blushingly admits she's had her share of thoughts about Harry, mostly since the DA lessons under Umbridge's reign and that she would at least want to try it. Daphne is hesitant but is determined to bring her sister back to the Greengrass family.

A very embarrassed Harry submits to the attentions of all three girls after Hermione very patiently and insistent shares her reasoning. Before long Padma learns what is going on and blushingly volunteers her assistance, she does find Harry attractive but honestly she finds the largest library she's ever seen more attractive, she is a Ravenclaw after all. When Luna later arrives: 'When do I get my turn with Harry?' 'Oh, you want to help with the research too?' 'Research? Oh, that would be nice too I suppose... but it will have to wait until after sexy-times with Harry'.

Fast Forward:
A year or so on and Hermione, Daphne, Susan, Padma and Luna are all Harry's very happy wives. Hermione as Lady Potter is pregnant with Harry's heir while Daphne has assumed the Ladyship of House Peverell and Padma becoming Lady Black. Susan and Luna retain their last names and will bear the future Bones and Lovegood heirs.

Pansy however becomes a contracted consort, still obligated to provide Harry with sexual pleasure no less than once a month and her consort status permits Harry to appoint her as Head of House Parkinson and thus releasing all of the Parkinson family members from being chattel to simply being members of a client house of House Peverell. Eventually she will bear Harry's children as the heirs of the Parkinson family.

While Daphne isn't able to get Astoria relinquished to the Greengrass family she does approve greatly when as her Head of House Harry signs a betrothal contract wedding an ecstatic Astoria to a smitten Neville Longbottom and making Neville not her new owner but merely her new Head of House.

Since having 'solved' Harry's slavery problem his wives and consorts have been devouring the other contents of the library. Rare magics, ancient potions, lost rituals, journals of historical figures, obscure records. Many scholars frequent their home wanting to acquire knowledge. For visiting wizards it can be quite frustrating waiting for a wife or consort of Harry to be able to spare the time to read from tomes that the men can't see. But for unattached female scholars the usual response is to temporarily (or not so temporarily) become concubines.

Eventually Castle Peverell becomes something like the equivalent of a magical university with a predominantly female student body, the best and brightest witches coming out of Hogwarts, Beauxbatons and Durmstrang enrolling as concubines to the Peverell family making Harry a very busy, exhausted and happy wizard.