Grover Underwood

Grover was a satyr and a friend of Percy Jackson. He was the individual who initially spotted Percy as a Half-Blood and brought him to Camp Half-Blood.

Role in The Lightning Thief
Grover discovers Percy as a Demigod in The Lightning Thief. he accompanies Percy on his quest to the Underworld.

Role in The Sea of Monsters
In The Titan's Curse, Grover is on the search for Pan when he is captured by the Cyclopes Polymetheus. Grover convinces Polymetheus he is a female Cyclopes, and Polymetheus plans to marry Grover. Grover develops an empathy link with Percy, telling him of the danger he is in. Percy travels to Polymetheus's isle to rescue Grover and the Golden Fleece. Grover plays a role in defeating Polymetheus.

Role in The Titan's Curse
Grover stops his quest for Pan temporarily to quest with Percy once again. During the quest, he comes to believe that the secret to discovering Pan is drinking coffee, and so he takes up the habit of drinking the beverage regularly.