Board Thread:Lore Discussion/@comment-73.21.174.250-20150718065553/@comment-6881629-20150718123508

Anu and Padomay are the two primordial deity's or forces that created the Aurbis along with the Aedra and Daedra. Lorkhan then decided to make the Mundus (the mortal plane) and convinced some Aedra to help, Magnus designed it the Aedra that are now know as the Eight Divines became the planets. Other Aedra gave all their power to the creation of Mundus and the center planet Nirn as well as Lorkhan his body becoming the moons Masser and Secunda. Magnus seeing so many Aedra giving up so much left punching a large hole though Oblivion making the sun many other Aedra followed making the stars.

The Aedra that stayed became the Old Ehlnofey ancestors of Mer and the Wandering Ehlnofey ancestors of Man. Eventually (and for various reasons) they became the races we have now, except for the Argonian's who came from tree's.

Beyond Oblivion is Aetherius (theres a handy fan made diagram here), where the Aedra not interested in creating Mundus went to and where the various afterlife's are, the different realms and planes appearing as planets and space could just be the way mortal eyes interpret it though.

As for who is the "good god" and the "bad devil" thats kind of hard to say there are the Divines and the Deadra but not all the Daedra are necessarily evil, you could say Akatosh and Mehrunes Dagon but some Mer would say Lorkhan was the devil for tricking their ancestors out of their immortality.

Thats a very very rough explanation and it also depends on if you go by in game or out of game sources, and the different races have their own different versions of it. All the blue text is a link to the relevant wiki page so click those to read more.