Born on Krypton, 20-year-old Kara Zor-El was sent on a rocket programmed to follow her cousin, baby Kal-El's rocket following the destruction of the planet Krypton. Tasked with looking after Kal-El on Earth, her ship had a malfunction and she was trapped in stasis for decades; finally arriving on Earth years later she awoke to discover Kal-El fully grown and acting as Earth's champion, Superman.
Their intended roles reversed, Kal-El teaches her how to use her powers responsibly while Wonder Woman takes her under training and Batman provides her with the necessities to begin a new life on Earth.
- Supergirl (Vendor)
- Supergirl (Metropolis General Hospital)
- Supergirl (Fortress of Solitude: Power Core)
- Supergirl Illusion
- Supergirl (Brothers in Arms)
- Superman will contact you to locate Supergirl, who disappeared while investigating the rampaging metahuman patients at Metropolis General Hospital. She is being held captive by Doctor Psycho inside. Doctor Psycho would also conjure hallucinations of her, Power Girl and Wonder Woman in battle.
- Supergirl, located in the Meta Wing of the JLA Watchtower, will initiate the Level 30 mission to locate and assist her cousin, Superman, who is currently inside the Daily Planet building that is being shrunk and bottled by Brainiac.
- Supergirl is called upon by the Justice League to investigate reports of metahuman experimentation in a LexCorp-funded wing of Metropolis General Hospital. She finds extensive evidence of metahuman experimentation conducted by Dr. Psycho and attempts to liberate the meta-humans. She is thwarted and her DNA sampled by one of the new metahumans supported by the Secret Society of Super-Villains working for Lex Luthor.
- The following items can be acquired by defeating Supergirl:
- Supergirl's Kandorian Battleboots (epic) – Slot: Feet – Stats: 90 Defense, 24 Health, 50 Might – Requires Level 11 – Style: Supergirl
- Supergirl is an iconic opponent for villains in Alternate Metropolis in the Brothers in Arms operation.
- Supergirl first appeared in Action Comics #252 (May 1959).
- Supergirl is voiced by Adrienne Mischler.
- As the two are separate versions of each other from alternate Earths, Power Girl's and Supergirl's hearts beat in perfect sync with each other.
- Supergirl is proficient in hand-to-hand combat from training with the Amazons of Themyscira.
- While in the comics her skirt is blue, in DC Universe Online Supergirl's skirt is red; possibly taking inspiration from the Supergirl (1984) film, which in turn could have been inspired from the original "Supergirl", Super-Girl's outfit from Superman #123 (1958).
- Supergirl attends Metropolis University disguised as Linda Lang, the niece of Lana Lang. The duo live together in Hammersmith Tower.