Priscilla is a crossbreed of a Dragon and some other being, cast into the Painted World of Ariamis because of what she was. A description of her soul explains that she is a "crossbreed bastard child and antithesis to all life".
Her supposed doll is discovered in the Undead Asylum on the player's second visit which opens up the portal into the Painted World via the massive painting in Anor Londo. She stands in the tower at the edge of the ruins in the Painted World and watches over all who share the world with her. She acquired the power of Life-Hunt, an ability only she can wield. She is said to be so powerful that even the Gods feared her.