Lakshman went to Indrajit and challenged him. When Indrajit came out of the Devi’s cave, the monkeys bit and scratched him and threw impure substances in the sacrificial fire so that he could not perform the yagna.
In the end, Indrajit took the permission of his father Ravana, consoled his wife Sulochana and confronted Lakshman in the battlefield with a deafening roar. Lakshmana also gave him a fitting reply. There was a mighty battle between the two valiant warriors. Indrajit used many of his magical weapons but Lakshmana was more than a match for him and countered every move he made. At last, Indrajit was killed by well-aimed arrow of Lakshman.
When Ravana heard about the death of his beloved and brave son Indrajit, he was drowned in sorrow. The entire Lanka fell under a cloud of sadness. Mandodari and the other queens blamed Ravana but he was not ready to hear anyone’s words. He armed himself to go to battle.
Meanwhile Rishi Agastya came to Rama and taught him the Aditya Strotra.
Ravana energized his forces by his rousing speech and galvanized them to enter the battlefield with renewed enthusiasm. There was a terrible battle between Rama and Ravana. Injured by Rama’s sharp and well-armed arrows, Ravana fainted and fell in his chariot. His charioteer quickly took him away from the battlefield. But as soon as he regained consciousness, Ravana returned to attack Rama in the battlefield.
Death of Indrajeet, Ramayana – The Epic Story