How would we define demonic?
Would a loving god or a demon demand from you to (under certain circumstances) kill your relatives?
"If thy brother, the son of thy mother, or thy son, or thy daughter, or the wife of thy bosom, or thy friend, which is as thine own soul, entice thee secretly, saying, Let us go and serve other gods, which thou hast not known, thou, nor thy fathers;" (Deuteronomy 13:6)
"Thou shalt not consent unto him, nor hearken unto him; neither shall thine eye pity him, neither shalt thou spare, neither shalt thou conceal him: But thou shalt surely kill him; thine hand shall be first upon him to put him to death, and afterwards the hand of all the people." (Deuteronomy 13:8-9)
Who would order his followers to commit genocides? A (just) god or a demon?
"And Israel joined himself unto Baalpeor: and the anger of the LORD was kindled against Israel. And the LORD said unto Moses, 'Take all the heads of the people and hang them up before the LORD against the sun, that the fierce anger of the LORD may be turned away from Israel.'" (Numbers 25:3-4)
"Thus saith the LORD of hosts, I remember that which Amalek did to Israel, how he laid wait for him in the way, when he came up from Egypt. Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass." (I Samuel 15:2-3)
Would demons be the bringers of peace or of war? (I would suspect the latter)
"The LORD is a man of war: the LORD is his name." (Exodus, 15:3)
Is it a sign of demonic powers to send out evil spirits?
"And the evil spirit from the LORD was upon Saul, as he sat in his house with his javelin in his hand: and David played with his hand."
(I Samuel 19:9)
I could go on with many more examples ;)