This one kinda generic Veela!Draco-Mate!Harry fic, I cannot for the life of me find
I am fairly sure it was on AO3 and longer than 35K words.
Don't remember the author, title, or any tags and I don't think the summary was particularly helpful for finding anything I do remember.
Speaking of which, here's what I do remember:
Draco comes into a Veela inheritance over the summer, and once back at Hogwarts quickly discovers that Harry is his mate. Draco tells his parents who his mate is, and as his parent(s) (Lucius and/or Narcissa don't remember, might be both?) are Veela too, they're like 'oh damn, guess we're spies for the light now,' and promptly and genuinely do a heel face turn. The Malfoys request a meeting with Dumbledore and Harry to explain their new allegiance and why. Dumbledore and the Malfoy's have the vibe of 'the magic is the magic and will do what it wants' (not a direct quote). Harry though, does not like the situation, is kind of uncomfortable with it, but is reluctantly on-board none-the-less.
There's a bit of a schedule and living space rearrangement to be decided on, because Draco has a magical need for touch/proximity to Harry cause Veela, therefore, Harry and Draco get a special like two bedroom apartment thing in hogwarts. Might be mixing up my fics here but I could swear there was something about Draco needing to be tied to his bed at night if Harry didn't want NSFW things to happen to him.
Regarding schedules Draco fully expects Harry to be hellishly stubborn about as little of his life changing as possible, and was fully willing to yield to any decisions he made. Draco was instead surprised and delighted to find that Harry was quite willing, insistent even, on making quite reasonable compromises about their schedule, and who was allowed in their space. Harry expects Draco to have his friends and family over at some point, and as long as there was clear communication about who was coming over when, all was chill.
Early on the Malfoy's came to have brunch in Drarry's new Dorm-apartment-thing, that may or may not've involved giving both Harry and Draco books about Veela. Draco, because they weren't certain he'd be one and there's more for him to know; Harry, because he is wholly ignorant about what's going on with the Veela stuff.
In reaction to the Veela stuff; Ron was kinda like 'awe man, you get a Veela?! Damn I'm kinda jealous, but I learned my lesson in 4th year, and the Veela in question is Malfoy, so I'm just gonna move on with my life. Good for you tho.'
Hermione meanwhile, kinda mistakes the situation for something similar to the house elfs (S.P.E.W. type shit type shit). But Dumbledore quickly corrects her about it and also corrects her about house elfs. Because for elves it's not slavery its symbiosis, and for Veelas its some soulmate type shit type shit. Hermione then makes a teary apology to Harry thinking their friendship is over and Harry is just kinda like 'wtf are you talking about, ofc you're still my friend.' I have no further memories about Ron and Hermione's presence in the fic, but I'm reasonably certain that's because they are side characters, and the author didn't actually just forget about them and not include them further.
Later on there's some incident that sends Drarry to the infirmary unconscious. While out, a female slytherin (Millicent Bulstrode?) kidnaps Draco, force-feeds him love, lust, and fertility potions, and off screen non-cons him because she was betrothed to him or something before the Veela thing. She fully expects to get out of this scot free as she's taken fertility potions herself, and the only thing Veela can live for if they no longer have a mate after finding them, is their children.
Meanwhile, Harry wakes in the infirmary like 'where's draco?' and Dumbledore and Pomfrey are like 'got kidnapped, looking as fast as we can'. Harry gets the house elves in on the search for Draco. Then Harry remembers that earlier it was revealed that Dobby was never actually abused OR set free (maybe was during brunch with the Malfoys), and as a Malfoy elf he'd be able to find Draco faster and easier than other elves. Dobby finds Draco, rescues him, ties up the girl, and tells them what happened. The Authorities go get the girl and confirm that she is NOT pregnant due to Veela magic bullshit, and definitely would have suffered severe consequences regardless of any pregnancy.
However as a consequence of the non-con Draco went through, his inner Veela is FREAKING OUT to the point of being suicidal. The only way to prevent that, is for Harry to do NSFW things to Draco (not even full-on snu-snu, just stuff). And at this point in the fic, Harry has genuinely come to care for Draco, and although he isn't quite ready for that kind of intimacy, he is willing to suck it up and leap forward a little to calm the Veela down and assure it that Harry still wants Draco.
There something about a Veela authority (Council?) that came to check up on Drarry when they first got together, and that handled the Non-Con-er. When the person from this authority was interviewing Harry and Draco about the crime Harry explicitly asked for the harshest sentence possible for her.
Early on there was a plot point about delaying Voldemort's discovery of the Malfoy's allegiance changing by convincing him that Harry could be turned into a Death Eater. Which involved staging a public argument with Dumbledore, which Harry took to have a genuine argument with dumbles over something.
This was almost certainly a different fic, but there is a small chance of there being something about Harry using his parcelmouth ability to replace Snape & Lucius' dark mark with like a brotherhood bond to each other?
It was set after 4th year, and it wasn't post hogwarts cause Voldemort was around (if in the background). I think it was post year 5? cause something something 'you can have your family and godfather in here because i'd want mine to be, but they're dead and sirius was wrongfully wanted for mass murder' or something like that. But I don't know if it was a 6th year fic or an alternate 7th year fic.