Kthara's exact origins are uncertain, but she claimed to have been in high standing in Satan's Council of Hell. She also claimed to have been ten thousand thousand years old. She referred to having been freed after that length of time, perhaps referring to the length of time she had spent in Hell.
Kthara was summoned by the unwitting Gloria Hefford of the Church of the Dark Father, who performed a satanic ritual (invoking the Triad). Kthara instantly took possession of Gloria, stealing her soul in the process, and using her as the vehicle to escape her imprisonment. Another member of the Church tried to rush in to save Gloria, but Kthara stole his soul as well, killing him.
Kthara slew nine to eleven more victims.
Both Satana and the Son of Satan were drawn towards Kthara and Gloria for varying reasons, but Kthara manipulated Daimon into believing Satana was the source of the evil he had detected, and Kthara amplified his powers and influenced his mind so that he could destroy her. Unbeknownst to Kthara, Satana was revived and restored by the Basilisk. Disturbed by slaying his own sister, Daimon returned to Gloria's house, only to have Kthara reveal herself, drain his energy and bind him in preparation for a sacrifice as her twelfth victim. His sacrifice would allow Kthara to free her Ravagers on the Earth to claim and rule it.
Satana returned and confronted Kthara, who responded by summoning a group of minor demons to slay her. Satana freed Daimon, but when she and her brother proved unable to injure the demon mother, Satana then summoned the powerful Basilisk from within her. The Basilisk smashed Kthara, rent her body and ravaged her soul, and dragged her, screaming, back to Hell.
Kthara somehow escaped Hell once again and took possession of the spirit or form of Jedediah Ravenstorm in the ghost town of Lawless, in Southern Arizona.
The energies in Lawless were detected by both the Son of Satan and Mr. Fantastic, who sent the Thing to investigate. As Ravenstorm, Kthara attacked the pair and had them at her mercy, until Daimon realized who she really was and cast off her illusions. Daimon next skewered Kthara/Ravenstorm with his trident, driving Kthara's demon form from Ravenstorm's body/spirit. However, as Kthara dropped her hold over Ravenstorm, she also released the souls of the people of Lawless, who had been held in thrall by Ravenstorm's curse for one hundred years. Before they passed into eternity, the souls had but one craving: revenge. The spirits swarmed over Kthara, rending her limb from astral limb, until both she and the spirits faded into nothingness.