PLEASE, READ THIS! IT'S IMPORTANT!

Just wanted to say that, while pretty much all events in Canon happened in the same way here, up until Harry goes to Dumbledore's office to view Snape's memories, there are still some small differences.

For one, Harry loves, to the point of obsession even, both defensive magic and the Dark Arts themselves (though she tried to convince herself that her interest in the Dark Arts is only due to the fact that, to learn to protect herself from them, she needs to know them intimately). Therefore, she loves them much more than even Harry in canon. DADA is her favourite subject by a long shot, once again, more than Harry. So much so that, even during first year, she would spend hours in the library (and borrow books from the library) to study as much as she could about curses, counter-courses, jinxes etc, even more advanced than her current year of study. This means that she's very good at duelling, en par with an Auror or a Death Eater easily. She has a very vast knowledge of both Defensive Magic and Offensive Magic.

Also, she got O's in Charms, Transfiguration and Herbology in her OWLs, as well as DADA, of course (she failed History of Magic like in Canon, mostly because she had a vision in the middle of the exam, and a A in Astronomy). She also took, beside Divination and Care of Magical Creatures, Ancient Runes as well. But then switched to Arithmancy in her fourth year, instead of continuing with Divination. (Since the third-year curriculum of Arithmancy is theoretical, she studied it on her own the summer between third and fourth year, buying the yearbook for third year Arithmancy). She got E's in her OWLs in these two subjects as well as Care like in Canon.

About Potions, she pretty much hated it until her sixth year. She got an E in her OWLs by the skin of her teeth (and that's only because she wanted to be an Auror and needed the grade in Potions). She got into Slughorn's class like in Canon and like in Canon found the Prince book. But, unlike in canon, figuring he was an ex-student at Hogwarts and that maybe he left other books as well, she went to the Room of Requirements to ask the room to find all copies of the Half-Blood Prince books, not only sixth year Potions.

Thanks to the book, she developed an interest in Potions as well. She didn't only memorize the better instructions of the sixth-year potions, but all other recipes of the potions for all other years as well (seventh year included). But, not only that, she also learnt to understand Potions in a way she had never been able to before because her hatred towards Snape and his hatred towards her made learning from him impossible. She also learnt other spells the Prince created, not only the ones inside the sixth year potions' book, like Sectumsempra or Levicorpus. She not only found books on Potions belonging to the Prince but also books about Occlumency and Legilimency (and she learnt both – once again the hatred between her and Snape making her unable to learn from him), and books about Dark Arts and Defence. She can also cast wordlessly, unlike Harry from Canon.

When she used the Sectumsempra on Draco, and Snape asked her to bring him all her school books, she left the Prince's books in the Room of Requirement, the Room of Hidden Things, inside a bottomless, featherlight bag. She then went to retrieve it later. She didn't leave the Prince books in the Room of Requirements. When she found out who the Prince really was, she thought about throwing all the books away but then decided that so much knowledge couldn't be lost like that, no matter where it comes from.

Therefore, in this story, though she loses every 'personal' memory (her name, who her parents are, her life with the Dursleys, her year at Hogwarts, even Voldemort), she still remembers everything she learnt, she just doesn't remember where she learnt them from. Not only she remembers how to cast every spell she has ever learnt, to brew every potion she has ever brewed etc, she also knows how to cast spells she has only seen other casts or even spells she has only read in a book (which I think it's very possible because Harry successfully casted Sectumsempra on his first try in Canon and he had only just read the spell, nobody taught him how) – there are limits, of course, if the spell is based on a particular emotion like the Patronus, or the Unforgivables (though she knows how to cast the Imperius successfully – and she can fight it off, of course, like in Canon – and the Cruciatus – in this story she successfully casted it against Bellatrix at the DOM – and it's very possible that, without memories she will learn to cast the Avada Kedavra successfully as well).

Moreover, she learnt Latin and Ancient Greek in Primary School. Since she knew how to read Ancient Greek, she read Herpo the Foul's books in its original language. For those who don't know, Herpo is the first known wizard who successfully created a Horcrux. During the Horcruxes' hunt, to find as much info about Horcruxes as they could, Harry and Hermione read all the books they could find that even mentioned Horcruxes in passing. Harry went even further and read all the books Herpo has ever written (he was a Parselmouth and a spell crafter). Some of those books were, of course, written in Parseltongue as well, therefore only Harry could read it (not Hermione I mean). Remember that she's basically obsessed with the Dark Arts as well as Defensive magic, so she would never pass such an opportunity up.

Also, she never tried to create her own spells but that doesn't mean that she won't. Both Ancient Runes and Arithmancy can be used to create spells, wards and rituals, and she took those at Hogwarts. Also, Herpo the Foul explained how he created his own spells (his books are like journals, not really like published books).

Also, once again because this Harry is obsessed with Dark Arts and Defensive Magic, she made use of the Black Family library (which is something I've always found frustrating in canon. You have a huge library that actually belongs to you and you never even went inside, what the hell?).

Also, for the sake of this story, Lily was distantly related to the Gaunts, distantly related enough not to have inherited the Parselmouth ability (Harry 'inherited' the ability from Voldemort because she is a Horcrux but the Horcrux only awoke a dormant ability, therefore even if she stops being a horcrux and she has children, those children will inherit almost certainly the parseltongue ability).

Also, Sirius sort of blood-adopted her when she was born. When he became her godfather, he sort of became her second father by blood as well and Sirius' heir – and therefore the Black heir – by blood as well. Moreover, still for the sake of this story, Charlus Potter and Dorea Black are born in the 1800's (Dorea in 1882 and Charlus is 1880). That means that, in this story, Dorea is actually the daughter of Phineas Nigellus, one of the previous Headmasters of Hogwarts. She was born as the 6th child and second daughter, after Arcturus Black.

Also, in this story, Charlus Potter comes from the main line of Potters. The Cloak of Invisibility was his at one point. At his death it went to his son. But this son never married (well, in the original timeline he never did, at least). Therefore, it went from him to Fleamont Potter – who was Charlus Potter's son's first cousin – and then to James and then to Harry.

I think that's pretty much everything. Sorry for the insanely long note but, since Harry won't remember things for a very long time (she will get flashes but she won't regain her memories until much, much later), I didn't want there to be any confusion about how she knew the things she knew in this story or about the differences from Canon.