Harry Potter!!

[Vampyr]

Originally Posted by Seth

Neville Longbottom?

I can't remember if he's halfblood.

He's pureblood.

But for all we know, Rowling could take one of these characters we "think" are pureblood, and find some way for them not to be.

I personally think it will be character that has been mentioned before, but hasn't played a large role at all.