Mercenary forces are usually hired by the wealthiest nations involved in the war. Mercenaries have a long history behind them, for they have been in existence since war first began. During this period many rulers hired trained professional soldiers to protect their states. Ironically, rulers of neighboring states would hire out their soldiers in order to make money off their services. Mercenaries may be considered one of the world's most secretive words.
Many nations are unwilling to admit their use of mercenaries.
A good example is the United States during the Vietnam War. Although mercenaries were needed to help in wars, they were not and continue not to be well respected or liked. Mercenaries were used mostly during desperate times of war, many times not even paid or treated well for their services. The common depiction of mercenaries shows them as brutal soldiers who pillage, rape, and torture the people and cities they occupy.