Manu was the first king to rule mother earth and saved mankind from the universal deluge. Manu is very honest and thus entitled to the name `Satyavrata` or `oath of truth`. Mahabharata depicts Manu as the person who was endowed with great wisdom and always dedicated to virtue. The entire human race has originated from Manu and thus known as Manavas. Brahmanas, Kshatriyas and other casts have descended from him. The ten children of Manu are Vena, Dhrishnu, Narishyan, Nabhaga, Ikshvaku, Karusha, Saryati, Ila, Prishadhru, and Nabhagarishta. These ten off springs of Manu practiced the rules of Kshatriyas. Manu had fifty other sons also but all of them died quarrelling with one another.

Each Manu rules during an eon called Manvantara and Fourteen Manvantara make up a Kalpa. In Purana, each Manvantara is ascribed to one Indra and one Vishnu Avatara. The Kalpa is a period that corresponds to one day of Brahma. The name of fourteen Manus are- Svayambhuva Manu, Svarocisa Manu, Uttam Manu, Tamasa Manu , Raivata Manu, Caksusa Manu, Sraddhadeva Manu (son of Vaivasvata), Savarni Manu, Daksa Savarni Manu, Brahma Savarni Manu, Dharma Savarni Manu, Rudra Savarni Manu, Deva Savarni Manu, Indra Savarni Manu.

Currently the world is in seventh Manvantara 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.

Manu is also the name of the author of famous Hindu `Shastra` Manusmriti. Some Hindus consider that smriti contains the laws that should be followed by all Hindus. Manava Grihyasutra, Manava Sulbasutra and Manava Dharmashastra are texts ascribed to Manu. 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.