Islam was introduced during the 8th century, but unlike in the north it never really took hold outside of the major cities, and Hinduism remains the majority religion to this day. Deccan remained relatively immune to invasions by Greeks, Persians, Scythians, Turks, Mongols and other foreign peoples over the centuries, but in the late 18th century the region was conquered by the Kasi dynasty, which was of Bactrian origin.
Also around this time the subcontinent had attracted the interest of the fast-expanding European powers, in particular Albion. In 1809, after Shujah Shah Kasi had mistakenly sacked a trading post in an area controlled by the Albic East India Company, the Company obtained authorization to invade India and drive out the Kasis. Company rule was ended in the 1850's after a failed rebellion in the north threatened Albic interests in India, and the entire subcontinent was placed under direct Albic control soon after.
In 1944, at the height of the Third World War, China invaded Albic India. With the majority of Albic troops already occupied in the European theatre of warfare, and with the native Indian garrison of uncertain loyalty, the Axis forces rapidly gained control of most of the northern half of the subcontinent. The Azad Hind organization, formed to fight for Indian freedom, soon gained thousands of recruits to its cause and before long was strong enough to proclaim the Republic of Hindustan, independent from Albion. By the start of the Long Ceasefire, therefore, the subcontinent was divided between the Republic in the north and the Albic-controlled Indian Empire in the south.
During the Long Ceasefire there were many cross-border raids and skirmishes, the scars of which still play an important role in Indo-Deccanese relations. However, in 1958 Albion and the Republic finally agreed to peace terms, part of which included the provision that the Indian Empire should be granted independence as the Dominion of the Deccan. As such, neither Hindustan nor the Deccan played a big role in the resumption of the war and have retained relatively good relations with each other since.
The Deccan abolished the monarchy in 1972 and the present-day Republic of Deccan was formed instead. It remains nonetheless an active member of the Commonwealth of Nations and has good relations with Albion itself.