Deanna Troi

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 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 successfully passes the bridge officer's examination, gaining promotion to the rank of commander while maintaining her role as counselor.