Ada Veen is a fictional character from the novel "The Invention of Morel" by Adolfo Bioy Casares. She is depicted as a mysterious woman who becomes the object of obsession for the protagonist. The story explores themes of love, reality, and the nature of existence. In the narrative, Ada is part of a group of people who are trapped in a time loop created by a strange invention. This invention allows them to relive the same moments repeatedly, raising questions about memory and the passage of time. Ada's character serves as a catalyst for the protagonist's journey of discovery.