What did noble families fight over during the Warring States period?

Warring states got its name because there were 7 big states who were rivals over the control of the land and as well as the people. They keep on "war" whether what to get. Warring states never lasted because people are calling for unity. Noble families fight over the wealth and other riches they have. They are also worried about the lost of their people and as well as slaves. When the period didn't end, there is an increase in various intellectual officials on each states.