I have a headcanon that Draco was the only person who could actually stand against Harry in a duel after The Moldy Egg died.
So this is what happened when I elaborated on that but didn't edit. Update, I edited
Powers of a Wand
1. I believe that wands don't necessarily belong to one specific person. I believe their power levels come into play more than anything.
2. However, I still believe the wand chooses a host with similar personality because it feels better.
3. I believe that Harry and Draco have incredibly powerful cores, but where Harry's is brave and vibrant and new, Draco's is strong and silent and ancient.
4. I also believe that after the war there would be PLENTY of attacks in the eighth year, and not just on the golden, and silver trios either.
5. Though all the 8th years do, eventually, typically, decide to stick together.
6. But every once in a while someone will be brave enough (re: stupid enough) to attack Draco, whose magic is similar to that of a coral snake lookalike, sweet and harmless until suddenly you're bitten and you realize this one was quite poisonous and incredibly deadly.
7. Or unintelligent enough to attack Harry, whose magic is like a puma walking amongst the trees, just out of sight, and right when you think you've got him, it jumps down and, quite literally that one time someone tried to attack Hermione in Diagon Alley, takes your throat out with its teeth.
8. Now, I also believe that Harry and Draco both have similar, if not equal core levels, something they won't realize until fact 12 or so, but I digress. Where Harry's magic is mostly a wild gift from mother nature herself an apology of sorts, Draco's comes from millennia's worth of powerful ancestors building up more and more in each other until finally Draco was born.
9. Very, very rarely is anyone, student, teacher, or even auror stupid enough to attack Draco and Harry at the same time. Very rarely.
10. The first time Draco uses Harry's wand without thinking about it they don't notice until he's giving Harry his wand back. (And isn't that familiar.)
11. The first time Harry uses Draco's wand is an accident, and decidedly not life-threatening, well not much. He hopes. (Harry knocked his drink over onto Hermione and Draco's Arithmancy project.)
12. However, by the fifth or sixth (they've lost count honestly) time they use one another's wand, it's becoming quite clear that something between them works with each other.
12.5. Harry discovers he can still talk to snakes, and that his family is Indian and Draco is shocked to find his... friend... is actually as much an idiot as he'd mocked him for "Your family originated in India Potter, how did you not know that? Your name is Harpreet!"
"I didn't even know that until like fifth year!"
...if Harry's Muggle family suspiciously disappears, well, I certainly don't know who could've done it.
13. By the time Draco and Harry find out their cores are similarly sized they have gotten so used to using one another's wands to the point that it barely phases them. Pansy feints though. As did Ron... Let me tell you about the device.
14. The device was gifted to Neville by his grandmother for some reason or another, no one really remembers. Except for Pansy and Luna. They always remember... It, the device, flows with the power of the wizard until it can contain it, and then it glows until it reaches the appropriate power level.
15. Most purebloods have ancestral magic, while most Muggleborns have new magic. No one thought to test half-bloods before.
15.5. Which we'd be more surprised about if we didn't know the ministry.
16. Hermione will get right on that.
17. Most of the half-bloods have varying levels of wild magic with a mix of whatever ancestral magic that decided to pop up at that moment in time. I.e. Seamus' explosive magic was the wild side, his charmwork, however, came from his great-great-aunt Elda it is said.
18. This will start a very interesting experiment later on that month as a group project/experiment carried out by Theo, Hermione, Draco, and Andrew, Theo's boyfriend who's a seventh-year Hufflepuff. They're very excited to feel safe being out and about.
19. In the "present" so-to-speak, when Harry touches the floating ball and it takes up must the space in the 8th year common rooms, followed by glowing nearly as brought as the sun itself. Draco for one is not surprised. Harry did survive death twice after all. That is not a coincidence.
20. What is a surprise is when Draco's core grows just as big, and shines as bright as an unbridled full moon. The parallels are not lost on him. He's just more occupied with putting two and two together. Sort of.
21. "Potter! That's why we can use each other's wands! Because our magic is nearly the same!" Draco exclaimed, happy to finally put that mystery at ease.
22. "That explains so much honestly. Do you think it means anything though?" Harry asked, seemingly not caring much about it
("He cares plenty, Greg. Harry's just had a shit childhood, outward excitement is obviously rare from him, or have you not been here the past 8 or so years? This isn't nearly exciting enough for a strong reaction." Pansy says to her slightly obtuse friend)
23. "Nah," Draco says, still smiling, Harry might get lost in his smile for a bit, and Draco might stare into his eyes a little longer than usual.
24. Of course, Pansy will, quite literally screech ("Shut up Ron I don't screech.")
25. "You're impossible! Everyone knows only one of your soulmates can use each others wand!"
26. Draco, Lucius, and Narcissa did not, in fact, know this. If it's true then the three have quite a number of soulmates between them.
27. They do. Soulmates are not always romantic, and people have a habit of loving this family when they are given permission to do so. More on that in another ficlet.
28. Harry and Draco will be seen tumbling into their shared dormitories later that evening.
29. No one will notice nor be surprised when they use each other's wands in class five years later as Hogwarts professors. Draco teaches charms, and Harry teaches DADA, they've been doing it since seventh year after all.