Who ruled India first?

India was first ruled by democratic councils of trade guilds, merchants, craftsmen, who organized themselves to rule cities of the Indus Valley Civilization.
Indus-Valley-Seals

Trade Councils were the first rulers of Indian cities during the Indus Valley Civilization phase.

The history of India goes back several millennia to the Indus Valley Civilization. The rulers of this civilization could be called as the first rulers of India.

The civilization spread from about 3300 BCE to 1300 BCE.

Surprisingly despite high standards of building, high value of trade, there was no de-facto ruler.

The Indus Valley Civilization cities such as Mohenjo-Daro, Harappa, Rakhigarhi, Lothal, Shortughai and several other city-states were ruled by councils. These councils were formed by leaders of various trade associations, guilds, farmer associations, such as carpenters, builders, grain traders, etc.

The Priest King of Mohanjodaro

Some cities were even supposedly ruled by quasi-king like figures.

The figure(discovered in 1925-26 by K.N. Dikshit) on the left is the image of the supposed Priest-King, who might have ruled the Indus Valley Civilization, city of Mohanjodaro.

This figure is made up of steatite (a type of soft rock).

First King of United India

Chandragupta Maurya was supposedly the first king of an Indian empire. Born in a family of lowly origins, he was assisted by Chanakya, the well renowned Indian statesman in overthrowing the king Dhanananda, who himself usurped a governing council to become the king.

Maximum Extent of Mauryan Empire under Emperor Ashoka
Maximum Extent of Mauryan Empire under Emperor Ashoka, Source Wikipedia