 Just before giving himself over completely to host the spirit of Kronos, Luke bathes in the River Styx and obtains the invincibility of Achilles.Thalia Grace is the daughter of Zeus and Beryl Grace, a TV starlet.She is seven years older than her brother Jason Grace and appears in "The Lightning Thief, The Sea of Monsters, The Titan's Curse, The Last Olympian, The Lost Hero,The Blood of Olympus" and the "Dark Prophecy".