Manu is the progenitor of human beings who saved mankind from the deluge and rules in each eon under different name. He was the first king to rule mother earth and saved mankind from the universal deluge. Manu is also the name of the author of famous Hindu Shastra, "Manusmriti". Manu Smriti is an old text which consists of the discourse given by Manu. It is considered to be the law laid down for Hindus.

Descendants of Manu
The entire human race has originated from Manu and thus known as "Manavas". Brahmanas, Kshatriyas and other castes have descended from him. The ten children of Manu are;
1. Vena,
2. Dhrishnu,
3. Narishyan,
4. Nabhaga,
5. Ikshwaku,
6. Karusha,
7. Saryati,
8. Ila,
9. Prishadhru,
10. Nabhagarishta.

These ten off springs of Manu practiced the rules of Kshatriyas. Manu had 50 other sons also but all of them died quarrelling with one another.

Manwantaras of Manu
Each Manu rules during an eon called "Manwantara" and Fourteen Manwantaras make up a "Kalpa". In Purana, each Manwantara is ascribed to one Indra and one Vishnu Avatar. The Kalpa is a period that corresponds to one day of Brahma. The names of Fourteen Manwantaras are;
1. Swayambhuva Manu,
2. Swarochisha Manu,
3. Auttama Manu,
4. Tamasa Manu ,
5. Raivata Manu,
6. Chakshusha Manu,
7.Sraddhadeva Manu (son of Vaivasvata),
8. Savarni Manu,
9. Daksa Savarni Manu,
10. Brahma Savarni Manu,
11. Dharma Savarni Manu,
12. Rudra Savarni Manu,
13. Deva Savarni Manu,
14. Indra Savarni Manu.

Currently the world is in 7th Manwantara which is ruled by Sraddhadeva Manu. There is a story in Puranas which connects Manu with the deluge. It is believed that the first incarnation of Lord Vishnu, the Matsya Avatar appeared before the first Manu, whose original name was King Satyavrata, while he was washing his hands in the river. The fish was small in size and asked king Manu to save it but kept growing larger and larger. The fish informed the king about the huge flood that would occur soon. Manu built a huge boat, which housed his family, nine types of seeds and animals to repopulate the earth when the deluge ended.