There's a clear separation between "god" and "angels". God is the creator, angels are a part of creation. Humans, planets, bacteria, granite are all things god created. God was never created, he has always been. Some christian sects seem to believe in a trinity, which is not necessarily polytheist if it's taken to represent different aspects of god. It seems like the trinity just represents different facets of god's personality, except with Catholics who seem to believe in a three-part god figure with several minor deities, just like pagans.