As Valmiki tells it
Valmiki Ramayana, Yuddha Kanda 105 to 109 · 3 min read
Rama had been fighting all day, and he was tired. Ravana's chariot was coming at him again across the field, and the gods had gathered in the sky to watch.
One of them came down to him. It was the sage Agastya, who had given Rama his weapons in the forest years before.
"Listen, Rama," he said. "There is an old secret that wins every battle. Praise the sun. Every god is in him, and he stays awake when every creature sleeps. Say this hymn three times and you will kill Ravana today."
He taught Rama the Aditya Hridayam, the heart of the sun, and went back the way he had come. Rama sipped water three times, looked straight at the sun and said the hymn. The tiredness left him. He picked up his bow, and from among the gods the sun called down to him, "Hurry."
Then the two chariots met. Rama rode the chariot Indra had sent him, with Indra's own charioteer, Matali, holding the reins. The fight was so terrible that both armies stopped where they stood, weapons in hand, and watched like figures in a painting.
Rama cut down Ravana's flag. Ravana struck at Matali, and that made Rama angrier than any blow aimed at himself. He cut off Ravana's head, earrings and all. Another head grew in its place. He cut that one off, and another grew. He cut off a hundred heads, one after another, and Ravana was still alive.
"These are the arrows that killed Maricha and Khara," Rama said, half to himself. "They killed Viradha and Kabandha. They went through seven sala trees and shook the ocean. Why do they do nothing to this one?"
The fight went on for seven days and seven nights without a pause, on the ground and in the air.
At last Matali spoke. "Why are you fighting him as if you had forgotten? Use the arrow Brahma made. The gods have said his time has come."
Rama remembered. The arrow had been made by Brahma for Indra, and Agastya had given it to him in the forest. The wind was in its feathers, fire and the sun were in its point, and it weighed as much as the mountains Meru and Mandara. It hissed like a snake when he drew it out.
He fitted it to the string, said the words over it, and let it go.
The earth shook. The arrow went through Ravana's chest and tore his heart, went down into the ground, and came back to Rama's quiver of its own accord. The bow fell out of Ravana's hand at the same moment as his life left him, and he dropped from the chariot.
Drums sounded in the sky and flowers fell on Rama's chariot. The sun grew steady and a soft wind began to blow.
Vibhishana, Ravana's youngest brother, who had come over to Rama's side, stood over the body and wept. Then he asked Rama whether he might give the king who had never once taken his advice the rites of the dead.
"Enmity ends at death," Rama said. "What we came for is done. Give him his rites. He is as much mine now as yours."
As Tulsidas tells it
Ramcharitmanas, Lanka Kand 101 to 103 · 2 min read
In the Ramcharitmanas Ravana does not fight fair. He fills the sky with ghosts and goblins and women with skulls in their hands, makes fire burn wherever the monkeys run, and rains sand on them until Lakshmana and the monkey king fall senseless. Then he makes a crowd of false Hanumans, all holding rocks, who close in on Rama from every side.
Rama breaks the whole illusion with one arrow.
After that he cuts Ravana's heads and arms off again and again, and they keep growing back, the poet says, the way greed grows with every gain. The gods and the sages watch and are frightened. To Tulsidas it looks as if the Lord is playing.
Then Rama looks at Vibhishana.
"Listen, Lord who knows everything," Vibhishana says. "There is a pool of nectar in his navel. That is what keeps him alive."
Rama is glad to hear it and takes up his arrows. At once the omens begin. Donkeys, jackals and dogs howl. Comets show in the sky, and the sun goes dark though no eclipse is due. Mandodari, Ravana's queen, feels her heart shake inside her. In the temples of Lanka the images weep.
Rama draws the bow back to his ear and looses thirty-one arrows together, and they fly like the serpents of Death. One dries up the nectar in the navel. Twenty take the arms, and ten the heads. The headless body still runs about the field until one more arrow cuts it in two. Even as he dies, Ravana roars, "Where is Rama? Let me find him and kill him."
The ground shakes when he falls. The arrows carry his heads and arms to Mandodari and lay them in front of her, and then go back into Rama's quiver.
And the light that had been in Ravana leaves the body and goes into Rama's face. Shiva and Brahma see it and are glad.