Among the Hidden
Actually, Luke didn't know if there was anyone else like him. He wasn't supposed to exist. Maybe he was the only one. (2.3)
His favorites were the handful of adventure books, the ones that let him pretend he was a knight fighting a dragon to rescue a kidnapped princess, or an explorer sailing on the high seas, holding tight to a mast while a hurricane raged about him.
He liked to forget he was Luke Garner, third child hidden in the attic. (7.8-9)
"I mean, you're another shadow child. Right?"
"Shadow--?" Luke wondered why his brain seemed to be slowing down. Was it just because she seemed several miles ahead of him?
"That's not the term you use?" she asked. "I thought 'shadow child' was universal. But, you know, an illegal, someone whose parents broke Population Law 3903. A third." (15.7-9)