Power Girl (real name Kara Zor-L, also known as Karen Starr) is a DC Comics superheroine, making her first appearance in All Star Comics #58 (January/February 1976).
Power Girl is the Earth-Two counterpart of Supergirl and the first cousin of Kal-L, Superman of the pre-Crisis Earth-Two. The infant Power Girl's parents enabled her to escape the destruction of Krypton. Although she left the planet at the same time that Superman did, her ship took much longer to reach Earth-Two.
Possessing superhuman strength and the ability to fly, she is a member of the Justice Society of America and the team's first chairwoman. Power Girl sports a bob of blond hair; wears a distinctive white, red, and blue costume; and has an aggressive fighting style. Throughout her early appearances in All Star Comics, Power Girl was frequently at odds with Wildcat, who had a penchant for talking to her as if she were an ordinary human female rather than a superpowered Kryptonian, which she found annoying.
The 1985 limited series Crisis on Infinite Earths eliminated Earth-Two, causing her origin to change; she became the granddaughter of the Atlantean sorcerer Arion. However, story events culminating in the 2005-2006 Infinite Crisis limited series restored her status as a refugee from the Krypton of the destroyed pre-Crisis Earth-Two universe. She was ranked ninth in Comics Buyer's Guide's "100 Sexiest Women in Comics" list.
Kara's father discovers that Krypton is about to explode, and places her in a spacecraft directed towards the Earth. Although this occurs at the same time that Kal-L's ship is launched, Kara's ship travels more slowly, and she arrives on Earth decades after her cousin has landed. Kara’s Symbioship is designed to keep her in stasis during the journey and provide her with life experiences and education in the form of virtual reality. The Symbioship allows her to interact with virtual copies of her parents and fellow Kryptonians within her home city of Kandor. By the time she arrives on Earth, Kara is in her early twenties. As mentioned in JSA Classified #1, her age at arrival has been retconned to about eighteen in post-Crisis continuity.
In Showcase #97, Kara is reclaimed by the sentient Symbioship and reimmersed into Kandorian society for a time. Several years of virtual time elapse, in which Kara is married and has a child. She is freed with the assistance of newspaper reporter Andrew Vinson, at which point she disables the ship.
Power Girl's existence is not revealed to the general public until much later; her cousin Clark and his wife Lois Lane provide her a family environment to assist her transition towards real life relationships. In her first recorded adventure, Kara assists Justice Society members Flash and Wildcat with containing an artificially induced volcanic eruption in China. She then joins Robin and Star-Spangled Kid to form a Super Squad to assist the Justice Society in defeating Brainwave and Per Degaton, who were causing disasters around the world. She pushes their base towards the Sun, the heat causing the villains to fall unconscious. Later, she becomes a full member of the Society when Superman retires from active membership.
Having been raised by the Symbioship with artificial Kryptonian life experiences, Power Girl finds it difficult to adapt to life on Earth. However, with the help of reporter Andrew Vinson, she adopts the secret identity of computer programmer Karen Starr (she obtains her knowledge in this field from exposure to Wonder Woman's Purple Ray on Paradise Island). On the pre-Crisis Earth-Two, Power Girl's closest friend is the Huntress, the daughter of the Earth-Two Batman and Catwoman.
The first contact between Power Girl and Earth-One's universe was on the crossover Justice League of America # 147, written by Paul Levitz & Martin Pasko, where the character shows her attraction to that reality saying, "It has a much nicer brand of Superman, y'know?"