Descendants of Vaivasvata Manu

Vaivasvata Manu is the seventh of the 14 Manus of the current Kalpa (aeon) so known as Satyavrata and Shraddhadeva..he is the son of Vivasvan and Saranyu (Saṃjñā). He is considered the progenitor of humanity. 

Shraddhadeva was the king of the Dravida Kingdom during the epoch of the Matsya Purana. 

Dravida is mentioned as one of the kingdoms in the southern part of present-day mainland India during the time of the Mahabharata, which links the origin of Dravidas with sage Vasistha. 

Vaivasvata Manu married Shraddha and begot ten other children named Vena, Dhrishnu, Narishyan, Nabhaga, Ikshvaku, Karusha, Sharyati, the eighth, a daughter named Ila, Prishadhru the ninth, and Nabhagarishta, the tenth.

According to the Matsya Purana, Matsya, the avatar of Lord Vishnu, first appeared as a shaphari (a small carp) to Shraddhadeva while he washed his hands in a river flowing down the Malaya Mountains.

The little fish asked the king to save him, and out of compassion, he put it in a water jar. It kept growing bigger and bigger, until the king first put it in a bigger pitcher, and then deposited it in a well. When the well also proved insufficient for the ever-growing fish, the King placed it in a tank (reservoir), that was two yojanas (16 miles) in height above the surface and on land, as much in length, and a yojana (8 miles) in breadth. As it grew further, the king had to put the fish in a river, and when even the river proved insufficient, he placed it in the ocean, after which it nearly filled the vast expanse of the great ocean.

It was then that Vishnu, revealing himself, informed the king of an all-destructive deluge which would be coming very soon. The king built a huge boat which housed his family, saptarishi, nine types of seeds, and animals to repopulate the earth, after the deluge would end and the oceans and seas would recede. At the time of deluge, Vishnu appeared as a horned fish and Shesha appeared as a rope, with which the king fastened the boat to the horn of the fish.

The boat was perched after the deluge on the top of the Malaya Mountains. After the deluge, Manu's family and the seven sages repopulated the earth. According to Purana, Manu's story occur before 28 chaturyuga in the present Manvantara which is the 7th Manvantara. This amounts to 120 million years ago.

In this 7th Manvantara, or reign of Manu, the demigods are the Adityas, Vasus, Rudras, Visvedevas, Maruts, Asvini-kumaras and Rbhus and the seven sages are known as Kashyapa, Atri, Vashista, Angira, Gautama, Agastya and Bharadwaja. The king of heaven, Indra, is known as Purandara.