I think it has been revealed that Firestar dies in the third (Night Whispers) Omen of The Stars book.
really?! he is one of my faves :,(
i think he either died in fading echoes when trying to fight off Russetfur, but he might've just lost a life.
He didnt die in Fading Echoes he still has one left
He doesn't die until The Last Hope. He died from his injuries.