Sarah Kerrigan

Sarah Kerrigan is one of the primariy characters in the Starcraft series. Introduced as a Ghost (psychic special operatives) in the first Starcraft series, Kerrigan is a member of the Sons of Korhal, a rebel force seeking to overthrow the Confederacy of Man. She's angered at the confederate goverment for the experiments they did on her. As siege is layed to the Confederate capital, Kerrigan finds her self abandoned by Mensk, leader of the rebellion. Contact is cut off, she is alone in the middle of the swarm, yet, the Overmind saw potential in her, and transformed her into Queen of the Blades, where she became eager to take her fight to those who betrayed her.

Background
(History prior to her appearance in Starcraft Episode One Mission Five)

Starcraft
Kerrigan is introduced in mission five of Episode One. It's revealed that Jim Raynor isn't keen on having a former Confederate Ghost assisting in setting off a revolt on the Antigan colony, and that the two know each other.

Kerrigan in popular culture
Kerrigan's gothic character has sparked wide interest. Including a song by youtubers Maduk and Veela called Ghost Assassin. Though the two haven't created an official music video for the song, several fans have given it a try.