Deanna Troi is a main character in the science-fiction television series Star Trek: The Next Generation and related TV series and films, portrayed by actress Marina Sirtis. Troi is half-human, half-Betazoid, and has the psionic ability to sense emotions. She serves as the ship's counselor on USS Enterprise-D. Throughout most of the series, she holds the rank of lieutenant commander. In the seventh season, Troi takes the bridge officer's examination and is promoted to the rank of commander, but continues as counselor. Troi appears in all four Next Generation theatrical films, and also made guest appearances on Voyager, Enterprise, Picard, and Lower Decks. Her romantic interests, family, and personal life are plot elements in many Star Trek: The Next Generation episodes. Depiction Deanna Troi was born on March 29, 2336, near Lake El-Nar, Betazed. Troi’s parents are Betazoid Ambassador Lwaxana Troi (portrayed by Majel Barrett) and deceased human Starfleet officer Lt. Ian Andrew Troi (portrayed by Amick Byram). An older sister, Kestra, died in a drowning accident during Troi’s infancy. Although Deanna Troi has little exposure to Earth culture, she attended Starfleet Academy from 2355 to 2359, as well as the University of Betazed, and earned an advanced degree in psychology. Deanna Troi serves as the ship's counselor aboard the Starfleet starships USS Enterprise (NCC-1701-D) and Enterprise-E under the command of Captain Jean-Luc Picard. In Star Trek: Nemesis, Troi leaves the Enterprise with her new husband William Riker, who has just been promoted to captain of the USS Titan. Troi's empathic abilities prove key to main shows, and other popular areas are her relationships and sexuality. In "The Child", she gives birth to an alien child. The Betazoid race has telepathic abilities. Due to her half-human heritage, Troi has only partial telepathic abilities, and as a result, is more of an empath with clairsentience. In Star Trek: Nemesis, Troi has expanded her empathic abilities, as she is able to connect to another psychic and follow that empathic bond to its source. In this instance, her ability enables Enterprise-E to target and hit the Romulan vessel Scimitar, despite the fact that it is cloaked. She is also able to communicate telepathically with her mother and other telepathic Betazoids or races with sufficient aptitude. Several species are resistant to the telepathy and empathy of Betazoids, such as the Ferengi, the Breen, and the Ulians. Early in the series, Troi finds herself working