People know as "cutters" are a good example of Biblical demonism. I know of a person whose daughter has this need to cut herself. A number of cults and pagan religions do/did things to draw blood in their rituals as well as ofering human sacrifices.
You won't believe this, Buz, but I've actually heard of a religion whose adherents ritually eat what they say is the body of their deity, and drink what they claim is its blood! Isn't that shocking??!!
Do I take your post to be, at least guardedly, a "yes" answer to the question "is epilepsy caused by demons?" Have my son and I really wasted all that time and money on neurologists and medicine for the last 25 years, when I could have had him exorcised? Are you telling be that Dilantin has anti-demonic properties? Are you completely unaware that self-mutilation is a psychiatric disorder somewhat kin to bulemia/anorexia? Are you really here in the 21st century?