The most remarkable possession case from the files of the German mesmerist Justinus Kerner.  The Maid of Orlach was a dairymaid over whom a White Spirit and a Black Spirit fought for control. The spirits were those of a sinning nun and a murderous monk. In the end, a house had to be destroyed to get rid of the possessing demon. The account of the maid is in Kerner’s 1834 book Geschichten Besessener neuerer Zeit (Histories of Modern Possession). 
[2. German: www.deutschestextarchiv.de ]
Strange events began in February 1831 at the farm home of a Lutheran peasant named Grombach, who lived in the tiny village of Orlach, Wurtemberg, Germany. The activity centered in the cowhouse and involved his daughter, Magdalene, the "maid." First, the cows were affected and poltergeist phenomena occurred. The cows would be mysteriously tied to new spots, and their tails were braided. Grombach kept watch but caught no visible person in the act. Magdalene one day received a sharp blow to one of her ears that sent her cap flying. From February 8 through February 11, mysterious fires broke out in the cow house. Then, Magdalene heard a child whimpering in the cottage house, but none could be seen.
A shadowy gray apparition of a woman appeared to Magdalene against a wall in the cow house. The spirit, which became known as the White Spirit, said the fires had been caused by an evil spirit, but that she had protected the family. She said that 400 years earlier, she had been a 14-year-old girl who was sent against her will to a convent, where she had committed a sin she could not reveal. She told Magdalene that the house must be destroyed by March 5 the following year. It told her, "Flee from the house! Flee from the house! If it is not pulled down before the fifth of March of the coming year a misfortune will happen to you ... promise me that you will do it!" The girl agreed.
The White Spirit appeared frequently to the maid until May. It also spoke in religious language and prayed the 112th Psalm. It read Magdalene’s thoughts and accurately predicted future events. No one but she could see it. In May, the White Spirit announced that she would not be able to visit for some time, and Magdalene would be persecuted by the Black Spirit, her evil companion. Magdalene should never answer him, no matter what happened.
The Black Spirit took various guises, such as frogs, a black cat, dogs, a headless horse, and disembodied male voices that followed the maid, mocking her. Then, it began showing up as a monk, tempting her with questions. The Black Spirit sometimes imitated the voices of neighbors in order to trick the girl into answering, but she held fast in her silence to him.
A bag of coins mysteriously appeared in the barn, and the Black Spirit said he put it there to compensate the maid for the box on the ear. Soon, the White Spirit appeared and told the maid that the money must be given to the poor. It was.
After this, the Black Spirit intensified his attacks on Magdalene. He appeared as a bear on July 15 and threatened to plague her if she would not answer him. From then on, he appeared in various monstrous, animalistic shapes, promising her money and threatening her with torture.
On August 21, the Black Spirit appeared as a horrible animal with its neck in the middle of its body. The maid fainted and was unconscious for several hours. The fainting episodes happened again on the following days. She could answer questions while entranced but could not remember anything when she awakened. She said that the Black Spirit came upon her and then disappeared when the White Spirit arrived.
On August 23, the White Spirit said she would protect Magdalene from harm but urged her to proceed with demolishing the family’s house, to end her suffering. The spirit said that the Black Spirit would take complete possession of her, but that she, the White Spirit, would take Magdalene away to a place of safety when that happened. These developments finally prompted Magdalene’s father to begin tearing down the house.
Beginning on August 25, Magdalene fell under intensified attacks from the Black Spirit, who was able to take over her body and speak through her mouth. A description of the manner of possession is as follows: In the midst of her work she would see the figure of a man clothed in a monk’s frock, which seemed to be made from black mist, approach and say, when she refused to answer his questions: "Now I will enter thy body in spite of thee."
Then she always felt him tread on her left side, seize her with five cold fingers at the back of the neck and then enter her body. She lost consciousness and individuality. Her voice was no longer her own, but that of the monk’s. The speeches which she uttered when in this state were worthy of a demon. Magdalene lay during the whole time with her head sunk towards her left side, and her eyes firmly closed; if the eyelids were raised the pupils would be discovered upwards. The left foot constantly moved up and down upon the ground throughout the attack, which frequently lasted four or five hours.
TRAUGOTT KONSTANTIN OESTERREICH [3, 4] stated of these occurrences:
[3. Possession Demoniacal And Other at Archive.Org ]
He (the possessing spirit) speaks of her, he knows quite well that she is alive, but he pretends that she is not there, but it is he who is there, and he pours out abuse and calumnies against the girl herself, whom he never calls anything except 'the sow.' ... During these fits the spirit of darkness now utters through her words worthy of a mad demon, things which have no place in this true-hearted maid, curses upon the Holy Scriptures, the Redeemer, and all the saints.
Her transformation of personality was so marked, said Oesterreich, that it was "exactly as if a stronger man drove the owner from his house and looked out of the window at his ease, making himself at home." Magdalene’s head would move from side to side while the Black Spirit was in her and then flop to the right when it left. If a Bible was placed nearby, the Black Spirit hissed like a SERPENT and tried to spit on it.
Magdalene remembered nothing from the attacks, except a faint memory of having attended church, presumably the way she perceived the protection of the White Spirit. Her left foot always went cold during the attacks, while her right foot stayed warm. But upon awakening, she could walk normally and felt nothing wrong with either foot.
Magdalene was taken to doctors, who said she had a natural illness and prescribed pills or medications, but none helped her. Finally Grombach took her to see Kerner. He tried magnetic passes two or three times, but the Black Spirit immediately neutralized them with countermovements of the girl’s hands. Kerner recommended prayer and a sparse diet. Magdalene did not respond to those, either, but Kerner was confident the matter would resolve itself according to the White Spirit’s promise of a cure by March 5.
Word spread about the girl’s afflictions, and crowds would gather to watch her when she was possessed. On March 4, the day before the White Spirit’s deadline, the White Spirit appeared to the maid at six in the morning. She confessed her sins: She had been seduced by the monk who was now the Black Spirit and had lived with him. When she tried to reveal his wickedness, he had murdered her. While the spirit spoke, a phantom black dog appeared and spit fire. The White Spirit reached her hand toward the maid, who touched it with a handkerchief. The cloth sparkled and then exhibited holes that matched a palm print.
The White Spirit said she was now freed from earthly concerns and said farewell. The maid was taken to a neighbor’s house, where the Black Spirit took possession, during which the girl ate no food. A huge crowd gathered to witness this and to question the demon, which gave accurate answers.
Deliverance occurred when the Black Spirit prayed during the night of March 4 and for the first time could say the words Jesus, Bible, church, and heaven. He confessed all of his crimes, including murders. He said there is a reckoning after death, and he must appear at the judgment seat a second time after he departed the maid.
The last wall of the Gromlach cottage was destroyed at 11:30 on the morning of March 5. The Black Spirit left Magdalene in an astounding transformation back to radiant health. She was never troubled again. Old bones were found in the debris of the house, including those of children, who people assumed were the victims of the monk.
- Oesterreich, Traugott K. Possession and Exorcism. [Among Primitive Races, in Antiquity, the Middle Ages, and Modern Times] Secaucus, N.J: University Books, 1966.
- Stead, W. T. Borderland: A Casebook of True Supernatural Stories. Hyde Park, N.Y.: University Books, 1970.