After the gods had killed all the demons, the mother of the demons, Diti started praying to her husband (one of the seven sages) for kids. Her husband Maharshi Kashyap blessed her with twins but the intention behind wanting those kids were not pure. That's why, Hiranyaksh and Hiranyakashyapu became arrogant and cruel when they grew up.

Guru Shukracharya, the teacher of the demons adviced Hiranyaksh to pray to Lord Brahma and ask for a boon of immortality. The problem is that no one but the gods can be immortal. So, the boon should be asked in such a way that it will make you immortal. After a year of hard perseverance and burning his body with the fire of meditation, Lord Brahma was impressed and appeared in front of him.

"What do you want Hiranyaksh?" Brahma asked. Now, please note here that Brahma knew about the intentions of Hiranyaksh but he can't punish Hiranyaksh for nothing and moreover, can't deny him the award for which he had burned his body with meditation for one whole year.

Hiranyaksh joined his hands and replied, "I pray to you that no God, demon or the animals I name can kill me."

Then Hiranyaksh listed all the animals he could remember and Brahma granted him the boon. Hiranyaksh then went on to defeat Lord Indra (king of the heaven) and Lord Yama (king of the hell) while ruling over the earth too. By this time, humans were also there, who prayed to these natural forces, to Lord Vishnu and to Lord Shiva too. No one prays to Lord Brahma but there is a reason for it. Anyways, Hiranyaksh started destroying the temples and killing the sages who were meditating.

Lord Vishnu looked at the slaughter of his devotees and heard their cries for help. Till then, Hiranyaksh had actually thrown the mother earth from her orbit and into the cosmic sea. She cried for help to Lord Vishnu. Lord Vishnu tried to remember the boon words and incarnated as a wild boar, ran and placed mother earth on her orbit again but Hiranyaksh had attacked him from behind. Lord Varaha turned around and fought him till Hiranyaksh was dead and downing in the cosmic sea.

Lord Varaha had become very angry for his devotees and was about to kill Hiranyakashyapu too but Lord Shiva appeared out of nowhere in front of him and urged him to calm down, reminding him that his only purpose was to kill Hiranyaksh and he couldn't kill Hiranyakashyapu yet because Hiranyakashyapu had done nothing wrong.

Lord Varaha closed his eyes and burned his body himself because his work was done. Apparently, Hiranyaksh had forgotten to take the name of one animal while asking for the boon, the Varaha...