Tripurasura (Sanskrit: त्रिपुरासुर) is a trio of asura brothers named Tarakaksha, Vidyunmāli and Kamalaksha, who were the sons of the asura Tarakasura. These three began to perform severe tapasya. They were then granted boons by Brahma to have three forts: gold, silver, and iron, which angered the Devas. Vishnu then made a new religion to make them evil, and the objective of killing the asuras was taken upon by Lord Shiva, which took three days on the battlefield, finally killing Tripurasura and destroying the three cities. This occurred on the full moon day in the Kartik month and therefore the day is celebrated as Tripurari Pournima. Legend The three brothers began to perform tapasya. For a hundred years they meditated standing only on one leg. For a thousand more years they lived on air and meditated. They stood on their heads and meditated in this posture for yet another thousand years. Brahma was pleased with this difficult tapasya. He appeared before them and said, "What boon do you want?" "Make us immortal", answered Tarakasura's sons. "I can’t make you immortal", replied Brahma. "I don’t have the power. Ask for something else instead". "Very well", then, said Tarakaksha, Vidyunmāli and Kamalaksha. "Grant us the following: Let three forts be made. The first will be of gold, the second of silver and the third of iron. We will live in these forts for a thousand years. These forts built in different worlds shall align once in every 1000 years. This combined fort will be called Tripura. And if anyone can then destroy Tripura with only a single arrow that shall be the death destined for us". This rather unusual boon Brahma granted. There was a Danava named Maya who was very good at building work. Brahma asked him to build the forts. The golden fort was built in heaven, the silver one in the sky and the iron one on earth. Tarakaksha got the golden fort, Kamalaksha the silver one and Vidyunmali the iron one. Each of the forts was as big as a city and had many palaces and vimanas inside. The asuras populated the three forts and began to flourish. The gods did not like this at all. They first went to Brahma, but Brahma said he could not help them. After all, the asuras had got Tripura thanks to his boon. The gods then went to Shiva for help.