Deanna Troi

Commander Deanna Troi is a fictional character in the Star Trek universe, played by the actress Marina Sirtis in the series Star Trek: The Next Generation and Star Trek: Voyager (the latter only in guest appearances), and in several Star Trek films. Troi was ship's counselor[?] on the USS Enterprise-D (NCC-1701-D) and also subsequently on the USS Enterprise-E (NCC-1701-E).

She was born on March 29, 2336 near Lake El-Nar, Betazed, to parents Betazoid Ambassador Lwaxana Troi (a Betazoid[?]) and the late Starfleet Lt. Ian Andrew Troi (a human). Because she's half Betazoid she's an empath[?], which often comes in useful when dealing with hostile aliens, though often she fails to detect intelligence in creatures with "a different plane of intelligence" until it's too late.

In 2364 she joined as a lieutenant commander on the USS Enterprise-D and in 2370 was promoted to commander.

In 2372 she was transferred to the USS Enterprise-E (NCC-1701-E).