Mando Hierarchy

"The Mandalorians, being a culture of warriors, are ranked based upon their combat experience and skill. Higher ranking society members train the lower ones, and when the current leader, usually referred to as 'Mandalore', dies the next high ranking member succeeds him, unless he has already handpicked a new one to take his place. The Mandalorian society is also tightly based on family values. Only a Mandalorian can officially lead the Mandalorians, not a Jedi nor a Sith; however, many times in Star Wars history the Mandalorians have been drawn into the armies of the Sith, most notably during the Great Sith War."

-wookipedia