From what I understand from the stories of minor deities, a god is created by mortals worshiping them. Either in life or in death. Kurgess, a athlete known far and wide around the realm was immortalized after his death by the very same athletes he competed against, giving him the base of worshipers to spread his faith around.
It's said that Kurgess might have been a demi-god by birth already and that it was Cayden Calean, his father who raised him to godhood. But it gives you an idea of how religions can spread. Just be famous enough that people already know about you and then die a martyr and there's a non-zero chance you'll become a minor god.
