Meghnadh or Indrajit as he was called by Lord Brahma was the greatest warrior in the epic Ramayan, probably much greater than his own father Ravan.
Meghnadh was the eldest son of Ravan and his wife Mandodari. At the time of his birth, Ravan instructed all the planets and constellations to be in such positions(ghars) so that his son becomes the mightiest warrior and extremely knowledgeable. When he was born his birth cry was so loud that it sounded like thunder and hence the name Meghnadh .
When Ravan went to indralok to fight all the devtas and lord Indra, he was eventually defeated by them and Indra captured him. When Meghnadh heard about his father’s capture, he immediately went to Indralok, defeated all the devtas and Indra as well. Then he took Indra to Lanka and decided to kill him to honour his father Ravan. Immediately Lord Brahma intervened and asked Meghnadh to free Indra. Meghnadh accepted Brahma’s request and hence was granted a chance to ask for a boon. Meghnadh asked for immortality, but Brahma politely declined as immortality is against the law of the nature. Instead, he was then granted another boon by lord Brahma that after the completion of the Yagna (fire-worship) of his native goddess, he will get a flying-magical chariot, mounting on which, he will win over any enemy in war and become invulnerable. But Brahma also cautioned him that whosoever would destroy this yagna would also kill him. Brahma also granted him another boon that he would only be killed by such a man who hadn't had sleep and food for twelve years. Brahma was so impressed by Meghnadh's skills in war and he who gave him the name Indrajit (the one who won over Indra).
After Ravan’s brother Kubhakaran was killed in battle, he send his son Indrajit to the battlefield.
On the first day of his battle, he killed all the 90 crore monkeys and 20 crore(half) sloth bears. Using the mighty weapon Nagapash (a dangerous weapon in which the enemy is blinded by thousand snakes ), he even defeated both Lord Ram and Lakshman and took their lifeless body to Pataallok(hell) for sacrifice. But eventually Hanuman went to Pataallok , saved Ram and Lakshman and then worshipped Lord Garud to save the monkey army.
Next day when Indrajit came to know that Lakshman and Ram are alive, he became very furious and vowed to kill them both. In the battlefield he used all type of sorcery(this was against the battle ethics) to kill armies of lord Ram, eventually Lakshman came out and started fighting Inrajit, to demotivate Lakshman and the monkey army Indrajit did such sorcery as if he was killing Sita in his chariot. This hit hard to Lakshman and in anger he pounced on Indrajit, taking advantage of lack of focus of Laksham he used Vasavi Sakthi against Lakshman, Lakshman fell unconscious, poised to die precisely at the following sunrise. His life was saved by Hanuman, who brought the Sanjivani plant for the weapon used by Indrajit and cured him.
When Indrajit came to know that Lakshman had survived again, he went to his native deity's secret temple to perform the yagna that would make him invincible. Vibhishan, Indrajit's uncle informed Ram about this, hence Lakshman and Vibhisan went to face Indrajit in the Yagnaagaar, where Indrajit would not touch any weapons. Indrajit fought Lakshmana with the utensils of the yagna.
Indrajit used the three Supreme Weapons (Brahmanadastra, Pashupatastra and Vaishnavastra) on Lakshman. To Indrajit's surprise each of the three weapons refused to touch Lakshman. At that point Indrajit realised that Lakshman was no ordinary human. Indrajit vanished briefly from Yagnaagaar, returning to Ravan at the royal palace and reported what he saw, proposing that he make peace with lord Ram. Ravan became furious and told Indrajit that he was a coward for having fled the battlefield. This accusation provoked Indrajit who briefly lost his temper, striking fear even at the Ravan's heart. He apologised and told his father that his primary duty as a son was to serve his father. He returned to the Yagnaagaar and fought Lakshman with all his skills . Lakshman slew Indrajit by beheading him with the Indrastra. It was possible only because Rama's brother Lakshmana didn't have any sleep or food for twelve years during their exile.
Though Indrajit is seen as a demon in Hindu culture, he was a mighty warrior who just followed his dharm.
