Back on Earth, she is attacked by the assassin Lobo and, in the ensuing battle, kills him while unleashing her rage. A Red Lantern power ring finds her and attaches itself to her, transforming her into a Red Lantern. Driven insane by rage, Kara wanders through outer space, attacking everyone in her way, until captured by several Green Lanterns and brought to Hal Jordan. Immediately recognizing a Kryptonian and unable to remove the power ring without killing her, he brings her to Guy Gardner, the leader of one of the two Red Lantern factions, who manages to restore her sanity. After some time under Gardner's tutelage and protecting the galaxy as a Red Lantern, she is discharged from the Red Lantern Corps, as Guy did not want her to die needlessly fighting against Atrocitus' splinter group. On her way back to Earth, Kara encounters the leader of the Worldkillers, who are revealed to be parasitic suits of armor. He attempts to assimilate Kara as his host, but she voluntarily subjects herself to kryptonite poisoning in order to stop him and eventually flies into the Sun and removes her power ring, killing her and removing him from her body. However, Kara is revealed to be immortal while in the Sun's core and she is restored to life without the power ring or any kryptonite poisoning, immediately destroying the Worldkiller. She later helps Gardner against Atrocitus and his Red Lantern splinter group.