Age Of Empires 3 vanilla unique unit
S tier - a lot stronger than the normal unit they replace A tier - decently stronger than the normal unit they replace B tier - a bit stronger than the normal unit they replace C tier - same as the normal unit they replace D tier - worse than the normal unit they replace
Credit to https://ageofempires.fandom.com/wiki/Age_of_Empires_III for the images.
