Princess Thalia was a fictional character from the storybook The Kingdom of Elysian, written by Benny Russell.
She was one of three monarchs who ruled in the magical Kingdom of Elysian. She was the leader of the eastern region of the kingdom and was described as having a "kind-heart" that "was forever with her people". In the story, Queen Neve's Crimson Guards invaded Thalia's kingdom, seized her throne, and imprisoned her people. The Queen thought that Thalia might have the Mercury Stone. Thalia escaped to the kingdom of King Ridley and requested his help in freeing her kingdom from Neve.
During the 23rd century, Doctor Joseph M'Benga often read this children's book to his daughter, Rukiya. In 2259, when an entity in a nebula transformed the crew of the Enterprise into various characters from that book, it was La'an Noonien-Singh who took on the role of Thalia, being given a pet dog Runa. (SNW: "The Elysian Kingdom")