Dear Student
The decline of Mughal rule and the rise of the Asaf Jahi dynasty are inextricably linked; and the Asaf Jahis arrived in Hyderabad and made it their own, much like the Mughals did with Delhi, not content to be mere subedars of a larger kingdom. A succession of political developments resulted in the Nizams ruling over the Deccan.
It all started with Aurangzeb gaining control over Golconda Fort and subsequently Hyderabad. With the conquest of the Deccan and then the south, Aurangzeb succeeded in spreading Mughal rule across the subcontinent.
Regards