In Himalaya
Bhayankarasur the new king of Asurlok was doing penance to please Lord Brahma. In every era, the Asuras did penance to please the tridev and with their boons, they tried to attack Swarglok. But this time Bhayankarasur's motive was completely different. He knew that if he attacked swarglok then the Devas would go to the tridev for help and the asuras would be defeated. But this time Bhayankarasur wanted to destroy the dharm on earth. With the rise of adharm, mother earth would be imbalanced which in turn would reduce the power of Devas in Swarg. Even the Devas depended on man's good work for their powers. This time he would spread adharm all over the world and it would automatically make the Gods weak. But for that, he had to be immortal so that no one could defeat him.
Bhayankarasur (chanting) "Om Namo Brahmdevaya, Om Namo Brahmdevaya,''
He was chanting Lord Brahma's name relentlessly for many years. His tapasya became so powerful that its energy created massive heat causing fire around him. Then Lord Bhrama came in front of him.
Lord Brahma "Son Bhayankarasur, open your eyes. I am happy with your penance. Ask me anything as a boon except immortality.''
Bhayankarasur ''O my Lord, I am happy that you came. I know that you cannot give me immortality, so I will ask for something else. Give me a boon that I will be killed by a person who is neither God nor mortal, not a Dev neither an Asur. Whose birth is a sin, but he is as pure as Devi Ganga. Who has the blessings of all Navagraha's (nine planets)? I will be killed only when that person wields the weapons of all tridev's together and those weapons can touch me only when they are purified by the powers of all Trivedi's."
Lord Brahma ''Tathashtu''.
Bhayankarasur (in mind) 'In this world, no one can fulfill all those conditions together. Even if Lord Vishnu takes an Avatar, he will still be a mortal. Even if there are some demi-gods present on earth, there is no one who can have the weapons of Tridevs together. Ha, Ha I am an immortal now. No one can defeat me.'
Lord Brahma (in mind), 'Bhayankarasur nothing is impossible in this earth. Everything that happens here is all previously designed by destiny. Now I know why Lord Narayan wanted a Devputra to born from a mortal women's womb. Bhayankarasur you called your own death today. But now we need to start Karna's training as fast as possible. I have to talk to Lord Mahadev and Narayan.'