When the sorting hat was placed on Stiles Stilinski's head, his face showed no nervousness to the people watching.
When the hat called out "SLYTHERIN!" a small smirk graced his face, making the people wonder how much more there was to the kid they met on the train with the bright eyes and the constant stream of words pouring out of his mouth.
When the Slytherins don't accept him- after all, why would they accept a mudblood who had somehow gotten into their house (nevermind that the war is over, some people just won't get over their prejudices)?- he smiles. When the rest of Hogwarts seems to avoid him- well, they tolerate his presence, and are decently polite (except the Gryffindors, and that's how he discovers there's some sort of rivalry between the two houses), nobody has gone out of their way to talk to him or help him when he gets lost. That's okay too. He smiles. It has a sharp edge to it.
Maybe the people seem to recognize that even though he's only eleven, his mind is sharp and his words are sharper, and his voice is laden with maturity that can only come from having already seen the horrors of the world. And he has. He's been able to see the thestrals since first year, after all.
When he comes back for his last year after spending the summer at home, students and staff can tell that there is something different about him. Dark shadows are under his eyes, his skin is pale, and his eyes and smirk are cruel. He carries himself around confidently, with the grace of someone who has lived for thousands of years.
They couldn't quite get rid of the Nogitsune. He finds that he likes it better this way. He feels stronger, more in control. He's filled to the brim with power. And Stiles loves it.
Void loves it too. Void loves that they have become one entity, the Void is Stiles and Stiles is Void, because Stiles is smarter than most people and has always been more willing to hurt people even before they had joined, and he knows they can do great things together.
Nobody knows all of this.
They only know that Stiles Stilinski looks like someone you really shouldn't mess with.
People will know, eventually. But they cannot make a move now, not when everyone is on such high alert since Voldemort's reign of terror was none too long ago.
Void wants complete and total control over everything. Everything in the Wizarding World, everything in the Muggle World, everything everywhere. Stiles is okay with that. (He did let him in quite willingly, after all.)
They will get it.
But they can wait.
They have forever, after all.