The main antagonist of the Greek hero Perseus is Medusa, a Gorgon known for her hair of living snakes and the lethal ability to turn anyone who looks directly at her into stone. Medusa's character serves to explore themes of fear and isolation as well as the consequences of vanity. Perseus's quest to slay Medusa symbolizes overcoming formidable challenges and fighting against terrifying adversities. Ultimately, the tale emphasizes the hero's bravery and the transformative power of confronting fears.