Pratardana, a descendant of Divodasa, is celebrated in Kaushitaki Upanishad (III – 1, 2, 3, 8, 9). He was an earnest and deserving student aspiring for knowledge of Brahman, the absolute reality.
Pratardana went to Indra, the chief of demigods, who offered him a boon, considering his ability and earnestness. But Pratardana replied – Indra you decide yourself the boon to be given to me as you know what is good for mankind. Indra said – No one chooses a boon for others. Hence you must choose. But Pratardana persisted with his request.
Thereupon, Indra said – Know me. That is the best boon. One who knows me is freed from every sin, including the killing of one’s own mother or father or a learned good man. Here ‘me’ stands for self, the absolute reality in every atma.
He went on to say that he is the prana (vital air), the very life principle, and is of the nature of pure consciousness. “Meditate on me as life and immortality.” He praised the prana (life breath) as the Supreme Reality. All the divinities are the projections of this prana. It does not decrease nor increase by any force, good or bad. It elevates the good people to higher regions and hurls down the bad people to hell. Pointing towards this context, Brahmasutra, on the basis of evidence from other Upanishads, has proved that the word prana here has been used for Brahman only.
Indra further said – Prana is Brahman, is the sovereign of all the worlds, in my very self. Indra said that he has realized the truth and hence asked Pratardana to contemplate on Brahman as his own self, as Indra did, to realize the non-dual reality (Vedanta Darshana – Brahma Sutra 1/1/28 – 31).
The Uttara Kanda of the Valmiki Ramayana mentions the farewell give by Sri Rama to Pratardana, the king of Kashi and friend of Ayodhya, who had come to Ayodhya to felicitate Sri Rama on the occasion of his coronation as the king of Ayodhya on return from the 14 years vanavasa (exile), after killing Ravana (Sarga 38).
Pratardana is also one of the thousand names of God mentioned in Vishnu Sahasranama Stotra, which is a part of the Anusasana Parva of the Mahabharata. Pratardana means exterminator. God is called Pratardana because at the end of the Kalpa (Era of creation), he exterminates all the creatures of the world. Otherwise also, asuras and rakshasas (demons) have been killed by him at proper times since the beginning of creation. Not only this, whoever takes birth has to leave the world one day under the rule of the Supreme Reality that is God, justifying the name Pratardana.