Sophia Pistis or Pistis Sophia (ピスティス・ソフィア Pisutisu Sofia) was a goddess who was born inside a vampire. For thousands of years she was reborn within the body of a vampire (known as a Psyche, or blood-producer) and forced to have a child to continue the Armash bloodline (the clan which Cecilia, Karin's maternal grandmother, came from). Once the next member of her bloodline was born she would be drained of her blood to help the other vampires reproduce, the only way to break the curse, according to James, was for the carrier to loose the Armash name. Unfortunately as the vampire she was reborn in could not drain the blood of another, they had a limited lifespan and would eventually die, becoming part of Sophia's life essence in the process and forcing her to be reborn in the body of another member of the bloodline.
About 1000 years prior to the current timeline, Edward, a vampire from the Edwardses and a brother of James' grandfather, had come to save her from imprisonment, which made other vampires mad, labeled him and his family traitors and smashed him into blood mess in front of Sophia's eyes.
She came to Japan in the body of Cecilia, Calera's mother, as Karin was the first child born after her death she was reborn inside of Karin. She was passed over to Kenta when Kenta and Karin kissed and was able to lead Kenta to where the Braunlichs (the clan which Daniel, Karin's maternal grandfather, came from) had taken her to because of it. According to James Marker, the vampires had relied on her for the sake of their own survival for centuries, however, after centuries their efforts had ceased to be effective, because that god (Sophia) was already "dead". After Karin's rescue, she declared because she was now inside of Kenta she was now free of her curse, but admitted after centuries had forgotten how to return to her home in the heavens. Eventually she was reborn inside of Karin and Kenta's daughter Kanon.