Question

who start sati pratha

Answer 1

The origins of Sati is quite debated. Sati is not mentioned in ancient scriptures like the Valmiki Ramayana and Vedas say the widow is often brought back to home.
So it's not sure

Answer 2

Sati Was Started For Preserving Caste

With the much discussed subject, now in India, about a so called "sati" of Charanshah, in village Satpura in Uttar Pradesh, some information about this evil in Hindu social system, may be not only informative but also educative to the masses who wish to build a new India on new values.