How God was born?

Why Zeus is always has a lightning on his hand?
Why Hades is not one of the 12 main gods?
Why is Athena a woman?
Whys is Anubis a wolf-face?

When I studying briefly on the mythology, each god of Olympus has their own looks, symbol, power and personalities. But gods don't really exist! How the people at very very old times know how actually their faces like?!

I'm very appreciate and impressed by the imagination and thinking of the ancient peoples. They can come out with something fantastic just from the thin air, so The gods were born within human minds. Without any of the information about the gods, those people still can come out with the actual look of them, even their power, the relationship between each other and what they symbolize. It may take them for a long time to figure out how all that, but they are the first one who come out with it!!!

Their imagination is unpredictable!!!! Without any reference or information, they can came out with those things!!! Even the parents of the gods, The Titans!!!!

If I was born in that ancient time, I surely won't think about the gods, or even a fantasy creature Haha~~ But I'll learn from them to be more creative in my future for design and drawing.