Once upon a time, there were two boys.
One boy walked and talked and did stuff. He went to school. He read books. He played games. Everyone knew him.
He was imaginary.
The other boy said nothing and did nothing. Nobody ever met him. He had a secret. He was only one who knew the secret, and because he knew the secret, he was invisible.
The imaginary boy was just like the invisible boy, except he didn’t have a secret. Because he didn’t have a secret, everyone could see him. Because they could see the imaginary boy, they couldn’t see the invisible boy.
The imaginary boy and the invisible boy went everywhere together. The invisible boy told the imaginary boy what to say and do, and the imaginary boy said and did what the invisible boy told him to do, and between them, when people looked at them, they saw a boy.
That suited the boys fine for a while. The invisible boy got to keep his secret, and the imaginary boy got to see what it was like to be real. The invisible boy got to see how people would respond to him, if he were visible, and the imaginary boy was just happy to do as he was told, because he didn’t really want anything, except to keep the invisible boy invisible, so he would be safe.
As time went by, however, the invisible boy realised he was lonely. Nobody loved the invisible boy, because you can’t love what you don’t know exists. And plenty of people loved the imaginary boy, but the imaginary boy couldn’t love them back, because he was imaginary. He only loved the invisible boy. So the invisible boy told the imaginary boy how to act like he loved people, and then he stood very close to the imaginary boy and pretended they were loving him instead, but that didn’t really feel like he was being loved.
Eventually, the invisible boy decided he’d had enough. He wanted to be loved. He wanted to be visible. He wanted to be real.
The only problem was, he would have to kill the imaginary boy.