Delhi Sultanate was a period in time, with around 4-5 dynasties ruling a large swath of India/Pakistan, rather than a single dynasty. The changes between the dynasties were the usual power grabs and infighting.

The Delhi Sultanate was weakened by a war with Timur, who had come down to India, apparently to 'remove' the Hindus. He did capture the city.

And during this chaotic period, along with some terrible administering by the last of the emperor's, Ibrahim Lodi, lead to one of his governors inviting Babur to India and the establishment of the Mughal rule in India.