Short answers, pulled from the story.
The Sur Empire was founded by Sher Shah Suri, of Afghan origin. He was crowned Emperor of Northern India for the second time on the 17th of May 1540 after defeating the Mughal emperor Humayun, though his dynasty's control of some territories dates to 1538.
Sasaram, in modern-day Bihar, served as the capital of the Sur Empire. It is also the location of Sher Shah Suri's tomb, a 122-foot-high mausoleum set in the middle of an artificial lake on the Grand Trunk Road.
Sher Shah defeated Humayun in two decisive engagements. At the Battle of Chausa, Afghan forces caught the Mughal army off guard as it crossed the Karmanasa River, killing more than 7,000 Mughal soldiers. At Kannauj, Mughal nobles fled the field, and Humayun escaped to Sindh, leaving Sher Shah to capture Delhi.
Sher Shah standardized the rupee as a silver coin weighing 178 grains, turning a generic term for silver coinage into the name of a fixed-weight currency. He also minted gold coins called Mohurs, weighing 169 grains, and copper coins called Paisa. The rupee remains the national currency in India, Pakistan, Nepal, Sri Lanka, and several other countries.
Sher Shah Suri was mortally wounded during the siege of Kalinjar Fort in 1544 when one of his own cannons burst in a gunpowder explosion. He died on the 22nd of May 1545, aged 73 or 59 by different accounts, two days after learning the fort had fallen.
The Sur Empire collapsed into civil war after Islam Shah Suri died in 1554, with five rulers contending for power in rapid succession. The Mughal reconquest concluded in the summer of 1557 when Sikandar Shah Suri surrendered at Mankot to Mughal forces led by Bairam Khan on the 25th of July 1557, after six months of resistance.