Halfway (Wizards and Faeries) by Stephanie Void

The world of Halfway is the anti-Harry-Potter: the wizard school is part of a shadowy organization that takes the students by force from their families. And the outside world isn't much better: if you are a wizard, you are looked upon with fear because of what you represent.

In the midst of this, in secret, twins are born: a boy and a girl. They are Halfway, the rare offspring of humans and a now-extinct race of faeries.

But the twins don't remain a secret for long. Temet, the boy, is taken as...