It is said that Vijayanagar had an army as big as 1 million when it invaded the muslim principalities of Ahmednagar,Bijapur ,Bidar and Golconda under Krishna Deva Raya.They did indeed muster huge numbers for the big fights perhaps as they did not want to be shamed by/terrified by the thoughts of right of first night and such things after conquest and submission.
The invasion of muslim principalities was not unprovoked.A prominent muslim under the payroll of the Vijayanagar kings in their court took a lot of money from the king for the sake of buying good horses,betrayed them and was granted asylum in the muslim prinicipalities.His name was half Muslim and half-Malayalee to the best of what I remember(just like present day Christians have a Christian firstname and a pagan surname).Possibly he was the offspring of Arab traders and shudra fisherwomen of Kerala.Might be that prompted him to act that way.
Krishna Deva Raya demanded that he along with the stolen money be returned back to Vijaya Nagar.The muslim principalities refused to comply.This led to an invasion.That is much more similiar to an asylum being granted to an enemy of Delhi Sultan by Hindu ruler of Kampili ,refusal of which prompted invasion of Kampili.Similiar to Bin Laden being granted safe haven by Taliban which resulted in the invasion of Afghanistan.The king is said to have given an arousing speech/inflammatory speech whichever way one sees it to his soldiers that caused them to completely rout the muslim armies.However muslim civilians were not molested in the defeated areas.
However under the reign of Rama Raya civilians were molested and mosques torched after the rout of Muslim armies.This enraged them and they unitedly inflicted a crushing defeat on the Vijayanagar forces.
Rama Raya who had previously allowed muslims to slaughter cows in their quarter of the city of Vijayanagar was asked to convert at the pain of death after his defeat at the disastrous battle of Tallikota.He is then said to have said 'Krishnam Vande Bhagavatham'.(I hail/I bow down to God Krishna).It was a statement refusing conversion.He was then said to have been beheaded.
Vijaya Nagar experienced glory for 200 years before this war and after this war Hindus of Vijayanagar continued to limp on for another 100 years.