However, there are other villains that play significant roles in the story:
* Kronos: The leader of the Titans and Luke's ultimate master. He is the main antagonist of the series and the primary reason for the conflict between gods and monsters.
* The Furies: Three female spirits who serve as the "Hunters of Hades," tasked with finding and punishing those who break their oaths. They are initially hostile towards Percy, believing him to be the thief of the lightning bolt.
* The Minotaur: A monstrous creature with the head of a bull and the body of a man, sent by Luke to attack Percy and his friends.
* The Monster in the Woods: A creature called a "Fury" (although not one of the Furies) that is sent by Luke to attack Percy while he is training at Camp Half-Blood.
It's important to note that Luke's motivations are complex, and he is presented as a sympathetic character despite his actions. His betrayal of Camp Half-Blood is driven by a desire to avenge the perceived wrongs committed by the gods, and he ultimately believes he is acting for the greater good.