Seeing them assembled in Tartarus, Percy felt as hopeless as the spirits in the River Cocytus. So what if he was a hero? So what if he did something brave? Evil was always here, regenerating, bubbling under the surface. Percy was no more than a minor annoyance to these immortal beings. They just had to outwait him. Someday, Percy's sons or daughters might have to face them all over again.
Rick Riordan, The House of Hades
adventure, young-adult-fantasy