Age of Empires II: Definitive Edition (PC) - Achievement - Raja of the People
Save both allied villages in "Born of Fire" on Hard difficulty.
This achievement triggers as soon as both Town Centres are saved. You start with a handful of cavalry. Time is of the essence immediately. You must split your forces and try to defend both Town Centres before they are destroyed. You do not have much time.
You should prioritise the enemy Armoured Elephants at each Town Centre (1 at each) as these inflict most damage to buildings. After this, try and take out the Cavalry, but fall back if needed. You can find a healer hero just to the West of the bottom right village, which will allow you to heal, regroup and attack again if needed. The main aim initially is to kill the Armoured Elephants and cavalry as these will still deal significant damage to the Town Centres, but you can take your time with the archers as they do minimal damage to buildings. It will probably take a few attempts as you really are rushed in the beginning to stop the Town Centres being destroyed.