A half-Betazoid empath, serving as the ship's counselor.
Deanna Troi is the counselor of the USS Enterprise-D in Star Trek: The Next Generation. She is half Betazoid and half human, and her empathic gift allows her to sense the emotions of others, which makes her a trusted advisor to Jean-Luc Picard.
Her relationship with William Riker, whom she knew before the series, is one of its warmest and most enduring, and the two eventually marry. She also has a complicated bond with her mother, Lwaxana, whose antics regularly embarrass her. Troi earns the rank of commander and takes a bridge officer's role, and she plays a part in the films and in Star Trek: Picard, where she continues her work as a counselor.
Troi is remembered as a compassionate and perceptive presence, whose emotional intelligence is as valuable to Starfleet as any technical skill.