In the comics, gods are those who have the primordial power of creation, seeded by the Demiurge. This had the byproduct of allowing life to form on the planet. They will be consumed, and their energy recycled, at the end of days by Atun, child of Gaea. Odin is in this group, as is Mephisto, Zeus, Yama, Erishkagal, Hela, and Cthon (author of the Darkhold).
It's more complicated than that, but there is a "god level", and a number of underworld gods complain about not being believed in and their underwords are stagnant with the lack of new souls.
Thor Annual #10, I believe.