Percy Jackson, and the Avengers
Percy's friends have all died. Including Annabeth. That broke him.
Percy returned to school, but he was different. He shut everyone out. His old friends from Goode didn't know who he was anymore, he's just so different, so hurt, so...broken. A lost cause, that's what some people call him.
The governments after him. He cant let them get him, and neither can Captain America