Leo Valdez is a fictional character in Rick Riordan's The heroes of Olympus series of novels. He first appears as one of the three protagonists in The lost Hero where he is a fifteen year-old demigod of indeterminate parentage who attends the Wilderness School, a boarding school for "bad kids".
After an attack por a group of storm spirits Leo learns that he and his friends, Jason Grace and Piper McLean, are demigods. The three of them are then escorted to Camp Half-Blood, a sanctuary for Greek demigods, where Hephaestus claims him as his son.