Gods are everywhere on the Discworld, a crucial element of the world's peculiar ecology that gives
power to belief and demands
resolution to any and all narratives. Gods exist in potentia in numbers uncountable, but the moment an event of any note occurs — say, two snails happening to cross at a single point — a god becomes tied to it and begins to manifest in the physical world. Most gods remain small and unknown, but a very few come to the notice of humanity, whose belief then shapes and strengthens them until they gather enough power to join the Disc's vast, unwieldy pantheon.
Gods on the Discworld exist as long as people believe in them and their power grows as their followers increase. This is a philosophy echoing the real-world politics of the power of religion and is most detailed in the novel
Small Gods. If people should cease believing in a particular god (say, if the religion becomes more important than faith) the god begins to fade and, eventually, will "die", becoming little more than a faded wispy echo.
