The Sisters of Eternal Mercy discovered the power of True Resurrection a long time ago. However, being resurrected is a daunting experience, and one that can sometimes deeply transform the resurrected in most unpredictable ways.
A bit like Santa Dolores (another Sister character), Doralys' resurrection was a traumatizing experience that turned her into a powerful psychic seer. Her reborn virgin spirit seems now irrevocably attuned to the sufferings of the living. She endlessly roams through the tangled fabric of time and souls, anticipating all the dreadful and painful things that will happen around her.
She can use this gift either to predict future events, or to turn the despair she lives in into a wave of psychic energy that will transform her enemies into hopeless wandering souls.