Angelology, is probably what you're looking for.
Technicly u are to call him God and the branch is angel in greek means God messenger.
Mercury
I assume that the question is: Who is the messenger of the Gods? Hermes in Greek and Mercury in Roman.
National Geographic Explorer - 1985 Messengers of the Gods 2-3 was released on: USA: 2 February 1986
Mercury was the Roman god of Messengers and Travelers. so he probably was the gods messenger.
Iris and Hermes were both immortal messengers.
Oracles messengers from gods sometimes masonary brick layers
The Spanish had weapons similar to those which the gods had. The appearance of the Europeans was similar to some descriptions of the gods. One of their gods was light-skinned with a beard who was supposed to return from the east on a boat. If they were not gods themselves, they may have been messengers from the gods.
Deer are considered the messengers of the Gods in Shintoism. Although that does not exactly answer your question, it is related.
Priests as intermediaries, and winged messengers in the absence of today's electronic communications. (however many people today for some strange reason still prefer winged messengers).
Angels were gods messengers, and they told the word of the birth of Jesus to humble shepards.
no there is only one god his name is God! he can save you if you ask him!