The phrase "entire army" means every single soldier or member of a military force. It refers to all the people who are part of the military unit, including officers, soldiers, and other personnel. Full definition
The Shining Force series had a very tactical / strategy element to gameplay, with the player taking command of entire armies of class based characters. (zeboyd.com)
I didn't want to focus on maximizing the usage of a singe troop or unit, I wanted to command entire armies and construct vast bases. (wolfsgamingblog.com)
They have the complete control of life and are able to decimate entire armies by just standing. (invisioncommunity.co.uk)