Omniscience→ Twilight

Jagger Volturi was a secret. A secret weapon that the Volturi kept for emergencies. No one knew of the boy's existence, not even the Volturi guard, only the three kings. The wing that he was lived in, in the castle, was off limits. Everyone was always curious as to what was down there but nobody had the guts to disobey the kings' orders. It wasn't until Jagger snuck out the room one day that his presence in the castle became known.

Or

In which the twin brother of a Volturi King falls for a playful boy that he didn't see coming.