Short answers, pulled from the story.
The Ancient Greek word daimon initially denoted a spirit or divine power without negative connotations. The term acquired its negative meaning through the Koine daimonion and was inherited by the Septuagint translation of the Hebrew Bible into Greek.
Anc Egyptian demons are divided into two classes: guardians and wanderers. Guardians are tied to specific places and can be benevolent if one knows the right charms, while wanderers cause possession, mental illness, death, and plagues as agents of chaos.
Zoroastrian concepts influenced Abrahamic religions like Christianity starting when Zoroaster elevated Ahura Mazda to supreme God and relegated daevas to demons. This dualistic cosmology shaped later Christian beliefs that non-Jewish deities were actually demons serving Lucifer.
Christian missionaries such as John Cassian in the fifth century declared pagan gods to be demons and servants of Lucifer who bring disorder to the world. This occurred during Medieval Christian Europe when monks assimilated Christian with non-Christian rites.
Paracelsus distinguished calodemons as good knowing ones and cacodemons as evil knowing ones within the sixteenth-century Renaissance magic tradition. He asserted these beings have bodies and flesh making them spirit-like but not human or angels.