Tasha Yar
Lieutenant Natasha "Tasha" Yar, played by Denise Crosby, is a character in Star Trek: The Next Generation. In the fictional series, the character served as chief of security aboard the USS Enterprise-D for the first season.
Crosby left the series near the end of first season, but reprised the role in "Yesterday's Enterprise" and "All Good Things...".
Read more about Tasha Yar: Development and Casting, Story Overview