Other forms: warlords
An aggressive military commander with extremely loyal forces is sometimes called a warlord. Warlords usually control a small territory within a country.
According to political scientists, warlords tend to gain power following the fall of a large empire and the rise of small, weak states in its place. The main thing distinguishing warlords from other types of rulers is that they have loyal followers who are well armed and obedient to the individual warlord rather than the actual government. The term warlord dates from the 1850s, but it wasn't common until the 1920s.