Although there are more than a few legends about the vastu purush or cosmic man, only the one inscribed in the Matsya Purana has gained such popularity. It is said that Lord Shiva once fought a terrifying battle with the demon Andhakaran. Legend has it that during this battle, from the sweat droplets of Shiva, a being was born. This was vastu purush. This humungous creation was blind with hunger the moment he was born. He became a ascetic to please the Lord, and he did. Happy with his prayers, Lord Shiva granted him a boon. And what vastu purush wanted was to devour the three worlds. Bound by his promise, Shiva, granted him the wish. He began devouring Earth. Fearing that their worlds too will soon be devoured, the Gods, lead by Brahma, decided to fight the vastu purush. Tired from the battle, the cosmic being, fell on the Earth.
A while later, he regained some of his strength and started attacking everything on Earth. The humans, started praying to Brahma to protect them from this demon. Brahma sent fifty three Gods to hold down different parts of this demon. The Gods used all their strength to hold down this creature – his head in the northeast, his hands in the south east corners and his legs in the south west corners. The Gods having settled on different parts of his body, the demon could no longer move and he prayed again, this time to Lord Brahma. Pleased with his prayers, Lord Brahma granted him a wish – that he will be remembered and worshiped before any construction. He is spread lying across the whole earth. Any construction done without the blessing of the vastu purush will result in misfortune to its inhabitants as the vastu purush is almost one with the Earth now.