Sons of God

Demons and angels were born out of the loss of knowledge of the ancient religions. Bene ha elohim, sons of the lord, were probably Canaanite gods, incorrect translations of the Hebrew text to Greek, translated it as "god's angels". The translation then to Latin changed it to filii Israël, sons of Israel. Based on Deuteronomium, Greek church fathers believed that every nation stood under the protection of it's own angel.

The passage that intrigues me most is Genesis 6:1-4 though. It tells how the filii Dei noticed how beatiful the human daughters were and each chose a wife. But God said his life spirit wouldn't stay with the humans as they are insignificatn beings and will only live for 120 years. As a result of the mating between his sons and the daughters, giants now lived on earth, the tyrants of the old time.