According to the description of Mahābhārata, Manu was the son of Brahmā, and Prajāpati was the son of Manu. The eight Vasu(s) were born of the womb(s) of the seven wives of Prajāpati. Dhara was the son of Dhūmrā. Dhruva was the son of Brahmavidyā, Candra was the son of Manasvinī, Anila was the son of Svāsā, Ahaḥ was the son of Ratā, Agni was the son of Śāṇḍilī, Pratyūṣa and Prabhāsa.
However, in some Purāṇa(s), the eight Vasu(s) are referred to as the sons of Kaśyapa. In another version it is said that Dakṣa Prajāpati gave away his ten daughters to marry Dharma. Sired by Dharma, eight sons were born out of the womb of Vasu, daughter of Dakṣa. They were Āpa, Dhruva, Dhara, Soma, Anila, Pratyūṣa and Prabhāsa. In Śivapurāṇa, Āpa has been referred to as Aya.
In Bhāgavata, the Aṣṭavasu(s) are named as follows- Droṇṇa, Prāṇa, Dhruva, Arka, Agni, Doṣa, Vasu and Vibhāvasu. From this, it appears that some of the eight Vasu(s) had more than one name.
In Mahābhārata and other Purāṇa(s), a detailed description is given about the sons of the Aṣṭavasu(s).
Dravaṇa and Hutahavyavaha are the sons of Dhara. In several Purāṇa(s), there is a mention of the five sons of Dhara and his wife Manoharā. They are– Draviṇa, Hutahuvyavaha, Śiśira, Prāṇa and Varuṇa.
Kāla is the son of Dhruva. He is the creator and destroyer of people.
A son called Varccā was born of the womb of Rohiṇī. One becomes energetic under the influence of Varccā.
The Vasu called Ahaḥ has four sons. They are– Jyoti (in another version, Vaitaṇḍa), Śama, Śānta and Muni.
Manojava (or Purojava) and Avijnātagati are the two sons of Anila and wife Śivā.
Kumāra was the son of Agni or Anala. He was reared by the six Kṛttikā(s), so he was also known as Kārtikeya. Śākha , Viśākha were the three younger brothers of Kumāra.
Maharṣi Devala was the son of Pratyūṣa.
The youngest Vasu Prabhāsa married the sister of Vṛhaspati. But that greatly learned lady ascetic̍s name is not mentioned in most of the Purāṇa(s). However, in one legend of Skandapurāṇa, it is said that this sister of Vṛhaspati was named Bhuvanā. Viśvakarmā, the architect-god was born out of the womb of Bhuvanā, and sired by Prabhāsa. According to Purāṇa, Viśvakarmā was also known as Bhauvana, because he was the son of Bhuvanā, In Brahmāṇḍapurāṇa, Bhuvanā is referred to as the sister of Viśvakarmā.
This Vasu gods, cursed bysage Vaśiṣṭha, were born in the earthly abode.
In ancient times, God Varuṇa had a son who was called Vaśiṣṭha. He was also known as Āpava. His sacred hermitage was by the mountain Sumeru. Several birds and beasts roam about there, and flowers bloomed in all seasons, tasty fruits and water were available always.
A cow-daughter called Nandinī was born out of the womb of Surabhi, daughter of Dakṣ, ṣand sired by Prajāpati Kaśyapa. She was very beautiful, greatest among the cows, and able to yield all that was desirable. The righteous Vaśiṣṭha received this Nandinī as his ̍Homadhenu̍.
One the Aṣṭavasu came with their wives to this hermitage, and started spending their quality time. At time, the wife of the Vasu called Dyu got fascinated with Nandinī, and repeated ly requested her husband to steal her, along with the calf. At her request, Dyu, with the help of his brothers, took her away. after some some time, Vaśiṣṭha could not find Nandinī anywhere. Using his ascetic powers he came to know that the Vasu(s) have abducted her. In anger, Vaśiṣṭha cursed the Vasu(s) that they would be born in the earthly abode.
The cursed Vasu(s), in fear, asked forgiveness from Vaśiṣṭha, but the sage did not withdraw his curse. However, he said that Dhara and the other Vasu(s) would be released from their human bodies within one year of being born, but the Vasu called Dyu, as a result of his deeds, would have to live a long life on earth.
He will be righteous, well-versed in all scriptures, engaged in the well-being of his father, be in paternal favour, and he will renounce amorous liaisons with women. Then the Vasu(s) went to goddess Gaṅgā and requested her, so that she could give birth to the Vasus in the earthly abode, and release them immediately after their birth. Gaṅgā granted their wish.
Elsewhere in Mahābhārata, the incident has been described in a different way. There it is said that the Vasu(s) unmindfully passed by sage Vaśiṣṭha, while he was busy in Sandhyāvandanā (the evening worship), without offering respect to him. So, sage Vaśiṣṭha became angry and cursed them to take birth in the earthly abode. The Vasu(s) prayed to Gaṅgā to become their mother, and wished to be get released after their birth. They also wished to be sired by king Śāntanu, son of Pratīpa.
Gaṅgā agreed, but she did not wish to completely thwart the king̍s desire for a son. Then the Vasu(s) said, they will donate one eighth of their individual energy, so that Śāntanu might have a powerful son. But that would not be able to father any child in the earthly abode. However, he would be a man of great powers. Gaṅgā gave her consent to this.
In Hastināpura, king Pratīpa o Candravaṃśa (the Lunar dynasty) was practsing tapasyā (ascetic worship) on the bank of Gaṅgā, hoping for the well-being and benefit of the world. One day, Gaṅgā, assuming the form of a beautiful lady, came out of water, and sat on the right thigh of the king. The king said, “O blessed lady, what can I do for you? You have taken shelter on my right thigh, which is the place for daughters and daughters-in-law. So you can be my daughter-in-law.” Gaṅgā agreed. The old king Pratīpa̍s son Śāntanu came of age, Pratīpa established him on the throne, and informed him about that divine lady, and with instructions that he should marry her, went away to perform ̍vānaprastha̍.
One day, going for hunting on the bank of Gaṅgā, Śāntanu got fascinated to see Gaṅgā in the shape of a beautiful woman, and wished to have her as his wife. Gaṅgā gave her consent with a condition that Śāntanu would not object to her actions, whether they are right or wrong. Śāntanu agreed to that. Now, the Aṣṭavasu(s) came to her womb, and after the birth of each of the sons, Gaṅgā drowned the child in her water, thus to release him from a human birth. Śāntanu, despite his grief to lose the sons, could not say anything. Thus the seven Vasu(s) got their redemption, but when Gaṅgā was ready to drown the eighth child, too, Śāntanu protested. Gaṅgā did not throw that child into water. This surviving child was that Vasu called ̍Dyu̍ and he came to be known as the great, virtuous and powerful Devabrata-Bhīṣma.