Where are your gods came from?

People with the setting that has gods - where are your gods came from? Were they always there or did they came into being later?

In my world Gods used to be mortals. A sister and two brothers who were traveling after their clan got wiped out in a raid of a rival clan. They were lost and freezing then they stumbled on an Ancient Primordial creature who was dying after a battle with another of it's kind. They consumed his heart and by doing so got powers that allowed them to ascend. Then they start to acquire followers and feed of there devotion to become stronger.

First brother was a proud warrior, dreaming of a powerful and vast domain for his subjects. Sister was a clan healer in live - so she was striving to nurture people under her care. And the last brother was a troublemaker with sharp wit and even sharper tough - so he encouraged in his followers independence and desire to be free. And so they rule over the empire they build, squabbling in a process as any family do.