CHURCH OF SATAN
Daemon in the original sense of the word was more of a benevolent or benign spirit. Daemon (classical mythology)
The Beginners Guide to Demonology is a short article that sums up this ancient history rather well. Basically stating that or course our modern conception is an invention of Christianity or recontextualization. The original word daemon is much more complex and harder to pin down but in essence it is a spirit, acting in all manners of ways from guardians to malicious attacks. They are more like animations of principles or concepts that can be summoned but act off the power given to them in the summoning.
Michael Taylor and the Ossett Murder case:
In short in 1974 in Ossett, West Yorkshire Michael was possibly cheating on his wife Christine with Marie Robinson the lay leader of their Christian Fellowship group. There was some yelling and Michael said he felt evil in him. The vicar called in other ministers. On October 5-6 1974 they cast out some 40 something demons and were aware that they had yet to remove the demons of insanity, murder, and violence, but allowed him to go home. At home Michael attacked Christine tearing out her eyes and tongue, almost her face, then strangled their poodle. He was found naked in the street covered in blood by a policeman.
Case wise he spent about 2 years in treatment and was released to only be charged of indecently touching a teenage girl in 2005 where he began exhibiting the same signs as before the murder and was ordered more treatment.