Though he wants to remain celibate, he marries Manasa on persuasion of his dead ancestors, who are doomed to fall to hell if he does not procreate.
The Hindu epic Mahabharata narrates that Jaratkaru was born in the lineage of the Yayavara Brahmanas and was the only heir of the clan.
Jara means "consumption" and Karu is "monstrous"; the sage had a huge body, which he reduced (consumed) by austerities.
In the first, shorter telling, Jaratkaru is described as being as powerful as a Prajapati, having performed severe tapas (austerities) and practised the vow of celibacy (Brahmacharya).
[4][5] In the second version, Jaratkaru is called a scholar of the Vedas and its branches, "controlled, great-spirited", and observant of great vows and austerities.
[2] The "great ascetic" has wandered the world and visited various pilgrimage spots and sacred bodies of water.
[5][3] The second Mahabharata version adds two additional conditions: that the namesake woman should marry him of her own free will, and that he will not support his wife.
[6] The poor and aged sage wanders the world in vain in search of a bride but does not find a suitable one.
As advised by the god Brahma, Vasuki has planned the marriage of his younger sister (known as Manasa in later texts) to Jaratkaru, the great seer in order to counter the curse given by the mother of the snakes, Kadru.
[5][2] Vasuki emerges and offers his younger sister Manasa to the sage, who accepts her after cross-checking with his criteria.
Jaratkaru warns his new wife that he would abandon her and his home if she ever displeases him, so she serves her eccentric husband dutifully.
The marriage is never consummated as Jaratkaru even refuses to touch Manasa, and sleeps separately under a fig tree.
[3][6] The Brahma Vaivarta Purana narrates that Jaratkaru oversleeps and misses the time of his morning rituals.
Chandi does not want Manasa to have a happy married life and thus asks her to wear serpent ornaments on her wedding night.