s wife, Andrea, was possessed by the demon known as Catherine, and she forced her to take her own life. Gabriel entered the priesthood, but was also possessed by Catherine. He cast her out, but lost his own right eye in the struggle, and quit the priesthood. As Gabriel left the cathedral, Desadia stepped from the shadows to greet him for the first time, speaking the words and using the voice of his dead wife, Andrea. Desadia soon after became Gabriel's partner in his career as an exorcist.
Desadia accompanied Gabriel to exorcise the demons We of the Darkness and Slime from Veronica Miller. She knew that Daimon would fail, but comforted Veronica's father, Dr. Miller, while Gabriel did his work. Gabriel exorcised the demons, who then possessed Dr. Miller, and covered Desadia in a smothering web of slime. Dr. Miller had anticipated that the demons would take him next, so he had taken poison. As he died, so did the demons trapped within him, and Desadia was freed from their trap.
Gabriel and Desadia traveled to London for an exorcism. This time Desadia knew that she would fail Gabriel, but that she would be needed nonetheless. While en route, the demon took control of Desadia, but Gabriel was able to drive it out by shocking her with a hard slap across the face. They eventually tracked Chesterton to Stonehenge, from which he was leading a black mass. When Gabriel confronted the demon, it had possessed Chesterton. It then claimed to be Satan, slew the rest of the Satanists, and mocked their worship. Gabriel tried to have Desadia kiss the possessed Chesterton, so her love would drive it out, but she couldn't bring her to do it because the demon had transformed his face into a hideous demonic form. Gabriel instead used the power of his love to force the demon out.
Desadia found Gabriel completely drunk in a bar after he had been missing for several weeks. He had been tortured by dreams and had sunken deep into despair. Desadia pulled Gabriel out of the bottle and got him back to work, and they soon exorcised a demon possessing the infant Jenny Christopher.
Desadia sensed the possession of the corpse of Esteban Ramirez by the demon Belial, and brought Gabriel to stop it. After Gabriel exorcised Belial, Andrea Gabriel's death certificate spontaneously combusted, and Gabriel finally accepted Desadia as his wife.
Desadia found Gabriel severely weakened and demoralized from his endless torment by demons. She convinced him to try to stop the demon possessing Bill Bohannon. In the course of the struggle, Desadia was knocked unconscious by the demon. Andrea's spirit left Desadia to join with Gabriel to bolster his spirit, allowing him to defeat the demon. Upon recovery, Desadia, no longer possessed by Andrea, now found herself without any memories. Gabriel realized it was now his turn to be strong for the both of them. Unfortunately, Gabriel didn't do so well at being strong, and Desadia was somehow eventually lost to him.
Gabriel's faith, now virtually non-existent, took another crushing blow after falling for the crusade of Rev. Joshua Crow. He got drunk again and was soon haunted by the spirit of Desadia, who pushed him to commit suicide. Gabriel actually had the gun in his mouth and was considering it, when Desadia told him that "Vermiphage is still laughing." Realizing that this was no hallucination, he shattered his bottle of liquor, and vowed to save Desadia.