The self-styled Queen of Blades, is a major character in Blizzard Entertainment's StarCraft series of video games and novels. The character was created by Chris Metzen and James Phinney, and her appearance was originally designed by Chris Metzen. Sarah Kerrigan was voiced by Glynnis Talken Campbell in the real-time strategy video games StarCraft and Brood War, and now played by Tricia Helfer in StarCraft II: Wings of Liberty.

Kerrigan originally appears in StarCraft as a twenty-six-year-old female Terran psychic, trained both physically and mentally as an expert espionage agent and assassin. Initially the second-in-command of the Sons of Korhal, a revolutionary movement headed by Arcturus Mengsk against an oppressive Confederacy of Man, she is captured by the insectoid Zerg and infested, turning her into a human/Zerg hybrid completely under the control of the Zerg Overmind. She becomes one of the Zerg's most powerful agents, but during the Brood Wars she replaces the Overmind, following the Overmind's destruction at the end of the great war, and gains control of the Zerg to seek dominance over the galaxy. Kerrigan's life before her infestation is further explored in the novels Uprising and Liberty's Crusade, while Queen of Blades elaborates on her infested character. As one of the major characters of the series, Kerrigan has been critically praised for her believability and character depth; a survey by GameSpot in 2010 put Kerrigan as the greatest villain in computer gaming.

Having been conscripted into the Confederate Ghost programme as a child due to her psychic potential, Kerrigan is described in the manual for StarCraft as never been given the chance for a normal life. Her rigorous training and the use of neural implants to control her mental abilities leave her a withdrawn and introverted woman. Despite this, Kerrigan exhibits qualities of courage and daring, and is an effective tactician. She is also described as a moral character, exemplified in her opposition to Arcturus Mengsk using the Zerg against the Confederacy. However, after her transformation by the Zerg, Kerrigan is freed from her inhibitions—as well as her neural conditioning—and indulges her darker traits. Her attitude, combined with her natural intelligence makes her extremely calculating and manipulative. A hint of her former moral sensitivity is to be noted when towards the end of the Zerg campaign of Brood War, she states how she feels weary of slaughter for the first time since her transformation. Kerrigan has also become far more physically aggressive, relishing in close quarters combat so much that one point in the novel Queen of Blades she begins absent-mindedly licking the blood of her victims from her fingers. The personality that Kerrigan displayed in the Heart of the Swarm Trailer seemed to be a combination of both attributes; during her conversation with Izsha the description of her crimes as "terrible" imply that to a degree she does feel genuine guilt for her crimes, and may seek to atone. On the other hand she is determined to crush opposition to her rule, and to exact her revenge on Arcturus Mengsk.