Garuda Purana is a vaishnava purana of the Hindu epic Mahabharata. In the story, the god Vishnu, using his divine powers, performs several tasks to kill the demon king, Garuda. The story is a part of the Hindu religious text known as the Vedas. 

After the death of Vishnu’s wife, goddess Satyaki, and his son, Lord Shiva, the god Garuda sets out to kill the demon king. As the story unfolds, it becomes clear that Garuda is not a mere mortal, but an ancient deity who has been declared a god by the Hindu pantheon. 

In the process of killing the demon king, Garuda learns the existence of Shiva, and as a result, the god Shiva is born from the mortal world. After this, a fire is kindled in the mortal world, and from it, a new religion, Shaivism, is born.