Question

Who dominated north India and claimed to belong to the sun or moon or fire families?

Answer 1

Rise of the Rajputs
"The most prominent feature of this transitional period is the rise of the Rajput Clans. Henceforth the Rajputs began to play a prominent part in the history of Northern and Western India. Almost all the kingdoms were ruled by families of Rajputs. Hence the period from the death of Harsha to Muslim conquest of Hindustan may be called the Rajput period.
India split up into numerous states due to absence of a paramount power
"Another feature of this period is that during this long interval, India was not permanently occupied by any foreign people. The country was split up into a large number of states ruled by local Hindu rajahs, often at war with each other. There was no paramount power to unite together under one rule the various kingdoms each of which pursued its own course quite independently. Hence the history of this period lacks unity and can not be conveniently presented as a continuous narrative.