A unique aspect to Rise of Nations is that citizens do not always remain idle after creation (as set by default in the options). After a brief moment, idle citizens will seek out work in nearby construction sites, unoccupied resource gather sites, construct buildings, and repair damaged buildings. This option can be enabled or disabled via the settings menu, or by changing a citizen's stance. The amount of time citizens will remain idle before seeking work can also be increased or decreased in the settings menu.
Citizens have the ability to fight enemy units or structures in melee, but they are very weak. However, from the Classical Age on, players may research Militia at a Tower, allowing Citizens and Scholars to take up arms and become Militia units. This will drastically improve both their offensive and defensive abilities. However, they will leave any task they are doing while in this state, only being able to fight while in it; and will still be fairly weak compared to regular military units and should only be used as a last line of defense or against raids.
As a nation advances through the ages, the appearance of the citizens will reflect the era the player is in. In the Ancient Age, citizens will resemble basic hunter-gatherer types. Reaching the Gunpowder Age, citizens acquire more clothing, resembling fashions of the Modern Period. Finally, from the Industrial Age on, citizens will resemble the working class of the present day.
Citizens are the only standard Civilian unit with the ability to attack (considering Militia as a transition from Civilian to Military). This attack is negligible at best, however; and represented as such by their amusing animation: Desperately kicking and flailing their arms in a vertical slapping motion in the face of an almost certainly doomed situation.