Warriors are the standard melee unit of Civilization Revolution and are available from the very beginning of the game.
With an A/D/M ratio of 1/1/1, Warrior units are capable of attacking and defending but are relatively poor at both. It is wise to form these units into an army or to just start building other units after some technologies have been researched. However, since all civilizations have the ability to produce Warriors as soon as the game begins and may use them to rush a weak or unprepared rival, it is advisable to make the best possible use of Warriors while they are available.
Warriors, like many other units, can gain experience by winning a certain amount of battles on the field, offering a 50% strength increase immediately. This can automatically render the Warrior units of other civilizations inferior to your particular unit (as long as they haven't gotten any promotions of their own).
Aztec Warriors are replaced by the Jaguar Warrior. Compared to the regular Warrior, it has the ability to heal after battle, which all other Aztec units share.
Zulu Warriors are replaced by the Impi Warrior. Compared to the regular Warrior, it has +1 movement, which can help provide more momentum.