Birth of Deific Beings

To become a deity, enough beings need to believe in your powers in the magical. A spell must be cast. A Space on a throne must be open or taken. The spaces in pantheons are not permanent. A god is merely a being who's been given abilities over a set of worldly things. Mortals decide who's in power above all. While this gives a deity immense power, the position is distinctly political. Fail to make mortals who pray to you happy and they'll either elect or invent a replacement. Some of the more savvy mortals of religious persuasions are fully aware of this power that they hold.