This is simply a theory and I probably am not the only one who thought of this but this is what I personally think why the deities were sent here, who sent them and why they used to walk the Earth but then left and other things that people have wondered about I think plan to make a video about this kind of thing, complete with music and images of all the deities

I believe all of the deities in this universe were sent by the All Creating Source and these highy intellgent beings desired to teach primitive beings and help them reach the after life and to be good and moral There were hundreds of deities working on the same side, and they were tasked to help the Earth, one of the most beautiful planets and help the primitive humans and reshape their lives. Humans walked upright, became more intellgient and many of them knew powerful technology as well as magic. The deities whil considered omnipotent, were far from it, as they were simply more powerful and wiser than humans. They enjoyed teaching humans many things and often descended down to help others and settle disagreements.

They themselves however have disagreements on how to do things. Yahweh, one of the most powerful desired things to be done differently when it came to offerings or certain requirements. Anu and Odin argued and the rest begin to quarrel. Some thought certain animals shouldn't be consumed as well. They all had the same afterlife, but because of disagreements on how people should attain salalvation, they devided up their after lives. Some deities were lenient while others were harsher on their punishments. Competion grew as well as jelousy where certain pantheons demanded more worship and more offerings than others. Eventually this led to war and for dominion of Earth as each pantheon had their own agenda. Entire countries and civilizations like Atlantis was lost because of their raw power.

However despite their in fighting, they felt remoreseful, and decided to divide their land up on
Earth. Even so, they were still bitter with each other but they did agree to not interact with humans as much since the deities were so powerful, they were afraid they would do much damage as they did last time. So most of the time they resided in their after lives and contacted the humans through spirit and preffered humans to take on certain tasks whatever they may be. The deities eventually left Earth all together seeing they had taught what they can, but also went on a mission to help themselves. Since despite their power and wisdom they were not infallible. Their infighting had almost destroyed the race they swore to help and teach. Once they felt they were mature enough they would return to Earth