Raisani is a Brahui tribe who were originally Tor Tarin Pashtuns. They are said to have come from Kandahar via Pishin and occupied the Thal-Chotiali area. From thence Rais Khan Tarin (the progenitor of Raisanis), with a band of his clan, occupied Kalat which along with Mastung and adjoining area was then occupied by the other Pashtun tribes and there was no trace of the Brahuis or Balochs in the area . With time Raisanis became completely Brahuized and they are now indistinguishable from other Brahuis.
Siwa, a Hindu raja and the first ruler of Kalat, is mentioned in the pages of history. After him, Kalat changed hands to the Mughals/Mongols, Mirwanis and Baloch Rinds successively. In the battle between the Mirwanis and Rind Balochs, Umar Khan Mirwani, the chief got killed. His widow, with her minor son, named Bajaru Khan took refuge in Mastung with the Pashtuns. Subsequently Bajaru Khan married the daughter of a local Pashtun notable. With the help of the Raisanis, Bajaru Khan defeated and killed Mandu Baloch and occupied Kalat. Bajaru Khan granted some land to the Siahi clan of Raisanis, which is still held by them. With the passage of time the Siahis merged with the Mengal Balochs and gradually lost their identity as Tarin Pashtuns and moved over to Jhalawan. Later, Mir Bajaru abandoned Kalat and became a recluse. The Mughals, who were waiting in the wings, occupied Kalat; however, the Raisanis along with the neighbouring Brahui clans, drove away the Mughals, and Mir Hasan Khan Ahmadzai Qambrani Brahui was proclaimed as the ruler of Kalat. The Brahuis from all over Balochistan concentrated in and around Kalat and established a powerful Khanate in the area.
During the rule of Mir Naseer Khan of Kalat, the southern portion of Khanate was named Sarawan and Sardar Abdul Nabi Khan Raisani was appointed as Khan of the area. He provided a contingent under his uncle Karim Khan to Ahmad Shah Abdali for invasion of India. He also accompanied the forces to India and gallantly fought in battles and earned the appreciation of King.
1- Rai Hatu Ram, Tarikh-i-Balochistan, p-172.
2- History of the Pathans by Haroon Rashid, p-114