Deanna Troi is a Star Trek: The Next Generation character. Actress Marina Sirtis played the character on the television series and several movies. Troi served as the ship's counselor. She is half human and half Betazoid. She can sense how others feel. Troi was born on March 29, 2336 on Betazed, her home planet. She had an older sister, called Kestra. She attended Starfleet Academy between 2355 to 2359. She also attended the University on Betazed were she studied psychology.