"Bel" is also the Akkadian word for "master", so it's been used to refer to many Mesopotamian and Levantine gods; for example, there is a story of a false god named "Ba'al" in the Old Testament, most likely referring to Hadad. That said, it has also been used to refer to Yahweh. This is also where the name "Beelzebub" comes from (it literally mean "master of flies").
It could also be short for "Belial", a demon in the Ars Goetia with the rank of King (there are only ten kings, so this would make Bel one of the eleven strongest demons). Belial is also one of the many names of Satan.
So I think there's much more to suggest that Bell is a demon rather than an angel.