Hiranyakasipu, the son of Sage Kashyap and Diti was a powerful and ambitious Asura. He was not satisfied ruling the Patala [the place under the surface of the earth]. He was not even satisfied ruling the earth and he set his sights on the Heavens.

Further, Hiranyakasipu's brother Hiranyaksha had been killed by Lord Vishnu in the incarnation of "Varaha" [the Boar].

And after the death of his brother, there was absolutely nothing to hold back Hiranyakasipu.

Hiranyakasipu hated the humans, the Devas and Lord Vishnu in particular and he hated them with a mad unexplained passion. Hiranyakasipu performed severe penance towards Lord Brahma and obtained a boon that he could not be killed by any creature created by Brahma and Hiranyakasipu further strengthened the boon by asking Lord Brahma that he could not be killed either within or outside any residence or during day or night time or in the grounds or in the heavens.

And after obtaining the boon from Lord Brahma, Hiranyakasipu was particularly vicious towards all the other people. Hiranyakasipu almost seemed to realize that he could not be defeated by any person and started behaving more and more atrociously towards the other people, making their lives impossible.

Hiranyakasipu even attacked the Skies and the Devas just could not do anything to him. Even Indra's Vajrayudham [Thunderbolt weapon] could not even dent Hiranyakasipu.

And Hiranyakasipu took it too far. He spread the propaganda all over the worlds that he was the most powerful man in all of the realms and that he was the ultimate God. Hiranyakasipu stopped people from worshiping the other Gods.

However, the problem for Hiranyakasipu arose not from any outside source but from his own son – Prahlada.

Prahlada was one of the greatest devotees of Lord Vishnu and no matter what anyone said, Prahlada would not accept his father as the ultimate God.

And Hiranyakasipu was furious. More than furious. It was so terrible that Hiranyakasipu actually tried to have his own son killed, not once but far too many times. And Prahlada survived all the times because of the grace of Lord Vishnu.

It was mainly to save Prahlada that Lord Vishnu incarnated as Narasimha. [In Sanskrit, Narasimha means Man-Lion. In this incarnation Lord Vishnu was half a man and half a lion.] And because Lord Vishnu had incarnated as Narasimha – Narasimha was not a creation of Lord Brahma and Narasimha dragged Hiranyakasipu towards the threshold of the palace [which was neither inside nor outside the house] and placed Hiranyakasipu on his thighs [which was neither the earth nor the skies] and during the dusk times, [which was neither night nor day] Narasimha killed Hiranyakasipu.

After the death of Hiranyakasipu, Prahlada was crowned as the king of Asuras.

Prahlada was pious and he ruled his people well. And there was some peace between the Devas and the Asuras.

Though Prahlada was the ruler of the Asuras, the Devas were always insecure with the Asuras and after the bloodthirstiness that Hiranyakasipu had shown, the Devas wanted to make sure that nothing like that was ever repeated.

The Devas wanted the Asuras back in the Patala. Which was why, despite the peace between the Asuras and the Devas, both the Devas and the Asuras were preparing for war against each other. And in the skirmishes between the Asuras and the Devas, more often than not, the Asuras lost.

Disgruntled, Prahlada gave up his kingdom and crowned his son Bali as the King of the Asuras and went to the mountains of Gandhamadana for meditating.

The newly crowned Bali tried to take the fight to the Devas. But the Devas were too powerful and with the help of Lord Vishnu, the Devas were almost invincible.

Defeated and disappointed, the Asuras took refuge in the hermitage of Shukracharya, their Guru. In those days, the acharyas were the ones who not only helped the army generals with the tactics ands strategies while fighting the battle but the acharyas were also knowledgeable in medicines which could cure the soldiers during battle.

And Shukracharya was a powerful acharya.

When the Devas learnt that the Asuras approached Shukracharya, they were all wary. Very wary. But they knew that Shukracharya being who he was, they could not attack the Asuras outright, while the Asuras were in Shukracharya's hermitage.

And so there was a stalemate between the Asuras and the Devas.