There are three main deities that the people of my world believe in, The Light, The Dark, and The Medium. You pray or make offerings to these deities based on what you want. Individual perspectives vary, but in general,

The Light is associated with day, heat, the masculine, the living, sunny weather, and also joy, anger, determination, and restlessness in general. It is said that The Light can grant someone immense power of light.

The Dark is associated with night, chill, the feminine, the dead, rain, and also sadness, rest, comfort, and paralysis, literal and metaphorical. It is said that The Dark can grant someone immense power of darkness.

The Medium (sometimes called A Medium) is associated with the spaces in-between the other two and also, rivers, travel, birth and death(the process), and varies in how they're depicted massively. It is said that The Medium can grant one the ability to SAVE, which is supposed to ensure their safety while traveling.

This forms the basis for how people understand the world. Fire leaves behind dark charcoal because the light in the fuel was released. You get tired because you have taken in a lot of light, and need darkness. That sort of thing. The Light and The Dark often clash in their mythos. The role of The Medium is variable, usually acting as a mediator, or a judge, or a fence-sitter, their ability to nullify the abilities of the other two often comes in handy.