Genly Ai is the main character in the science fiction novel "The Left Hand of Darkness" by Ursula K. Le Guin. He is an envoy from the planet Terra sent to the planet Gethen to persuade its inhabitants to join an interstellar collective known as the Ekumen. Throughout the story, Genly navigates the complexities of Gethenian society, which is unique for its ambisexual inhabitants who can change gender. His experiences challenge his understanding of gender, politics, and friendship, ultimately highlighting themes of communication and empathy across cultural divides.