Powers of a Wand
I believe that wands don't necessarily belong to one specific person. I believe their power levels come into play more then anything.
However, I still believe the wand chooses a host with similar personality because it feels better.
I believe that Harry and Draco have incredibly powerful cores, but where Harry's is brave and vibrant, Draco's is strong and silent.
I also believe that after the war there would be PLENTY of attacks in 8th year, and not just on the golden, and silver trios either.
Though all the 8th years do typically decide to stick together.
And every once in a while someone will be brave enough (re: stupid) 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 poisoness, and incredibly deadly.
Or unintelligent enough to attack Harry, whose magic is like a puma walking amongst the trees, just out of site, and right when you think you've got him, it jumps down and, quite literally that one time someone tried to attack Hermione, takes your throat out with his teeth.
Now, I also believe that Harry and Draco both have similar, if not equal core levels, something they won't realize until fact 10 but I digress. Where Harry's magic is a wild gift from mother nature herself, Draco's comes from millennias worth of powerful ancestory building up more and more in each other until finally Draco was born.
Very, very rarely is anyone, student, teacher, even auror or not, stupid enough to attack Draco and Harry at the same time. Very rarely.
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.)
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 project.)
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. Where Harry is mixed with something (your family originated in India Potter, how did you not know that? Your name is Harpreet! I didn't even know that until like sixth year!; if Harry's muggle family suspiciously disappears, well, I certainly don't know who could've done it.)
By the time Draco and Harry find out their cores are similarly sized they have gotten so used to using one another's wands that it barely phases them. Pansy feints though. As did Ron.
The device was gifted to Neville by his grandmother for some reason or another, no one really listened. Except Pansy and Luna. They always listen. It flow's with the wizards power until it can contain it, and then it glows until it reaches the appropriate power level.
Most purebloods have ancestrial magic, while most Muggleborns have new magic. No one thought to test halfbloods before. Which we'd be more surprised about if we didn't know the ministry.
Most of the halfbloods have varying levels of wild magic.
This will start a very interesting expirement later on that month as a group project/expirement carried out by Theo, Hermione, Draco, and Andrew. No idea who that last one is, some Ravenclaw who is fourth place in grades as far as their year goes.
However, 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 himself, well. Draco for one is not surprised. Harry did survive death twice after all, that's not a coincidence.
What is a surprise is when Draco's core grows must as big, and shines as bright as a full moon can shine. The parallels are not lost on him. He's just more occupied with putting two and two together.
"Potter! That's why we can use each others wands!! Because our magic is nearly the same!" Draco exclaimed, happy to finally put that mystery at ease.
"That explains so much honestly, huh. Does it mean something though?" Harry asked, seemingly not caring much about it ("He cares plenty Blaise. Harry's just had a shit childhood, outward excitement is obviously rare from him, or have you not been here the past 8 of so years?)
"Nah." Draco says, still smiling, Harry might get lost in his smile for a bit, and Draco might stare into his eyes a little harder then most.
Of course Pansy will, quite literally screech(shut up Ron I don't screech.) "You're impossible! Everyone knows only one of your soulmates can use each others wand!"
Draco, Lucius, and Narcissa did not, in fact, know this.
Harry and Draco will be seen tumbling into their shared dormitories later that evening.
No one will notice nor be surprised when they use each others 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.
