Ilyapa is the Incan god of weather, rain, and thunder.
This god was thought to carry a club and stones. He wore shining clothes. He was also human in form.
Ilyapa was the weather god of the ancient Incans. His sister was the Milky Way, who carried the jug of rain. When Ilyapa wanted rain, he would shoot a rock at the jug with his sling shot and break the jug, causing the water to fall from the sky. The sound of thunder comes from the breaking of the jug.
In times of drought, the Incans would tie up a black dog outside and leave it there until it was almost starving and dying of thirst. They would leave the dog there until Ilyapa took pity on it and let the rain fall.
Light and Dark Sides
Unfortunately, much of Incan myth has been lost to time and the conquistadors. So Ilyapa’s personality is not well understood. But, seeing as he’s a rain deity, it’s probably safe to say that Ilyapa could be considered a fertility deity. Rain is necessary for healthy crops and humans and animals, even in the mountainous regions of the Incas. Water is necessary for life–but too much water can kill. Floods and deluges can cause harm, and if Ilyapa gave too much rain, he could be a destroyer. So while Ilyapa could be a fertility god on the Light side, on the Dark he could be destructive. Even so, there can be good from a flood, especially in the ancient days when there wasn’t as much loss of human or animal life during a flood as there is today. Flood can redistribute essential nutrients and soil, and can change the environment for good or ill.
I think Ilyapa is an interesting god that very much embodies both the Light and Dark sides of his [potential] personality.