The Warrior is replaced by the following unique units:
It serves as one of the starting units in each game, along with a settler or a scout.
Build this melee combat unit for quick, early defense for your cities or as escorts for your defenseless Settlers. This unit is cheap to produce but weak, so you will want to make better units as soon as you are able. The Warrior can be an early scout that can protect themselves from Barbarians, animals, or any enemy unit.
When first trained in a city there is an advisor quote that the warriors serves as the backbone of the military.
The earliest military forces were simply the citizens of the city, armed with whatever implements they could use as weapons. Although a militia made out of warriors was inexpensive, they were no match for organized armies. Warriors were usually used as stopgap measures while waiting for superior units to be trained, or to defend a city that had been temporarily cut off from military support. In a crisis situation, an assembly of warriors is better than no defense at all.