Karu-Sil was born on Graxos III. At a young age, her family was slaughtered during a raid on her home. After several days, she wandered into the jungle in search of food. She was taken in by a pack of three fearsome beasts, who hunted with her and raised her as one of their own. Wanting to look more like them, she altered her appearance by sharpening her teeth into fangs. One day, Karu-Sil and her pack found a village by a river. There, she saw a boy, who approached her. She attacked him, and together with the beasts, killed him. They were found by Blish, the sector's Green-Lantern, who killed the beasts, thinking that they had also been trying to attack Karu-Sil. She was sent to an institution on Graxos IV, where she killed one of her psychologists. Karu-Sil was freed from the institution when she was chosen to represent her sector in the Sinestro Corps. She frequently used her power ring to make constructs of the three beasts she had grown up with.
Sinestro Corps WarEdit
Karu-Sil was one of the members of the strike force on Oa that freed Superboy-Prime, Hank Henshaw, and Parallax. She encounters Guy Gardner during the battle and when one of her beasts are hurt by the Green Lantern Corps member she rushs to its aide. Sil is next seen with a Manhunter hunting down GL rookies who are given a ring then killed by her. After awhile, she uses the Manhunter to recharge her ring and continues the hunt. She is last seen taking part in the battle of New York. Seeing Guy Gardner, Karu-Sil again goes after him. But this time Guy counters by creating a ring constructs of wolverines to her beasts.
Sometime after the Sinestro Corps War, Karu-Sil and several other female members of the Sinestro Corps are captured by Zamarons. Her body along with the two others are shown to the Guardians and Green Lantern Corps who visit the home world of the Zamarons. The trio are being subjected and conditioned to be members of the Star Sapphire Corps. The impurity of the subject to instill fear being eliminated, replaced by love it was not finished as she was released by Sinestro.