When Arjuna was pulled underwater by Ulupi, he entered the Nagaloka where he noticed the sacred fires.
Only after completing his religious duties, he asked Ulupi who she was because he never neglected dharma.
Ulupi answered that she was the daughter of Kouravya, the Naga King, and had been deeply attracted to Arjuna. She asked Arjuna to accept her. However, Arjuna refused, stating that he was observing a 12-year exile and was following brahmacharya.
Ulupi told Arjuna that she knew the reason for his exile and that the vow was specifically for Draupadi, and accepting her would not violate his vow. She said that if Arjuna rejected her, she would die from grief and added that helping someone in distress is dharma.
Agreeing to Ulupi’s reasoning, Arjuna spent his night in Nagaloka and, as he fulfilled Ulupi’s wish, she granted him a boon that no creature living in water would be able to overpower him.
The next morning, Arjuna departed from Nagaloka and continued his exile. Ulupi later gave birth to a son named Iravan.
