Who were the enemies of Hyder Ali?

The enemies of Hyder Ali were the Marathas and the British. The Marathas would defeat Hyder Ali in one of their battles and thus end up paying war indemnities to them. The British would become dogged foes of his son, Tipu Sultan in the years to come.

For further reading check the following articles:

• First and Second Anglo-Mysore War
• Battle of Porto Novo
• European Colonialism