Grover Underwood
In The Sea of Monsters, Grover is searching for the lost god Pan, god of the Wild, when he is captured by Polyphemus the Cyclops. Grover is trapped in a bridal boutique, mistaken for a female Cyclops and is taken to Polyphemus's lair in the Sea of Monsters, where he creates the empathy link between him and Percy. In his dreams, Percy sees how Grover is trapped by Polyphemus, the blind cyclops that once held Odysseus captive, and is about to meet the same gruesome ending as all satyrs before him, including his father, who went searching for Pan. Along with Annabeth and Percy's half brother Tyson, Percy journeys on an unapproved quest to find Grover. At the end, the Golden Fleece (a powerful healing item) releases Thalia's spirit from the pine tree that kept it.