In his deep voice, Jim rumbled, "We cannot win a fight with your former masters, but we can hide our activities from them. Hide your true nature and tell them that Sister Mary finally succumbed to her own dark desires. With her gone, her order has placed you in charge of the chapel and the cave unaware of your angelic nature. That should satisfy the agents of light and keep them away. If anyone comes looking around too closely, do with them as I have done with you."
Jessica smiled at her master's plan, "and what will happen to Sister Mary?"
"She will assure that any who enter the cave do not find it unoccupied. It would not do to have them realize that I am already reawakened." He sat on the bed and called the cat-creature into the room. With an unspoken command, Mary mounted the demon, gasping as Jim began to cum almost immediately. In a few short minutes, Mary's nipples began to show black through her white fur. The hair around her breasts and vagina began to darken as well, turning black and gaining a slight sheen. As she massaged her breasts, the sheen spread to her hands and they too started darkening.
Mary moaned as she rode on top of the demon. She saw what was happening to her, but she could not stop herself. Her entire body now looked like it had been coated in thick oil. The more that Jim pumped into her, the thicker that coat seemed to get. Finally, she found herself able to stand again. Her skin was no longer coated in fur, but instead was liquid smooth and a uniform black. As she walked out of the chapel, she could feel her body losing cohesion. Her extremities seemed to droop more than they should. She entered the cave, and small drops of black liquid fell from her body. They would pool for a moment before running back to Mary and melding into her feet. Finally she reached the back of the cave. Her body was losing cohesion, she could feel it. As she sank down into a pool of the black liquid, she thought of the surprise the next person seeking the corrupter's power would have when they were turned into a mortal woman.
With the chapel protected and the cave looking undisturbed, Jim had to decide how he would establish his power base.