Short answers, pulled from the story.
Humayun, born Nasir al-Din Muhammad on the 6th of March 1508, was the second Mughal emperor. He ruled from 1530 to 1540 and again from 1555 to his death in 1556 over territory in what is now eastern Afghanistan, Bangladesh, Northern India, and Pakistan.
Humayun lost his empire to Sher Shah Suri after defeats at the Battle of Chausa in June 1539 and the Battle of Kannauj on the 17th of May 1540. At Chausa, Sher Shah broke a truce and attacked the unprepared Mughal camp at night, forcing Humayun to swim across the Ganges to survive.
Akbar was born on the 15th of October 1542 at the oasis town of Amarkot, in the household of the Hindu Rajput ruler Rana Prasad Rao. His mother was Hamida Banu Begum, and Humayun used an astrolabe to fix the date by the position of the planets.
Humayun regained the throne with Safavid Persian support from Shah Tahmasp I, who supplied 12,000 cavalry. His general Bairam Khan led the army to a decisive victory at the Battle of Sirhind on the 22nd of June 1555, and Humayun sat on Babur's throne again on the 23rd of July 1555.
Humayun died after falling down the stone staircase of his library, the Sher Mandal, on the 24th of January 1556. Hearing the call to prayer, he tried to kneel, caught his foot in his robe, and struck his temple on a stone edge. He died three days later in his forty-ninth year.
Humayun's Tomb in Delhi was the first grand garden tomb in Mughal architecture and set the precedent later followed by the Taj Mahal. It was commissioned by his devoted chief wife, Bega Begum.
Humayun returned from his Persian exile with a large retinue of Persian noblemen, which shifted Mughal court culture. Persian art, architecture, language, and literature came to overshadow the dynasty's Central Asian origins, and thousands of Persian manuscripts from his time remain in the subcontinent.