The Mumbitanian Emperor's power and authority are absolute. The Overlords can do anything they like but if the Emperor wants something done it shall be done, without question. The Emperor was the head of the Committee of Overlords.
The Emperor was the head of state, a heavy head of government, and commander-in-chief of the Empire, and had absolute authority over the military and the Empire. The Emperor had sole power to appoint and dismiss the Overlords. The Emperor declared the budget and economy, ordered the Committee of Overlords into session, and dismissed it from meeting. The Emperor could introduce, pass, and veto Committee of Overlords legislation. The Emperor had the power to be a strong dictator, replace the Empire, and had the power to enforce laws and head every single decision. The Emperor also had power to appoint other officials in government and declare orders.
Ottak IV was the first official Emperor of the Mumbitanian Empire and most of the previous Imperial leaders had never made use of the title of Emperor. One, Theygus I, seems to have legitimately held the title briefly holding a Jakarr moon, during the long Jakarr war.
In the Declaration of Imperial Power, Ottak's speech had indicated that the Committee of Overlords would elect the Galactic Emperor, but after his death, the Mumbitanians had no wish for a man they would not know to rule so the Emperor’s son, Theygus became the new Emperor.
During the Mumbos Civil War, role of Mumbitanian Head of State was assumed by rogue Overlord, Lazaroc who declared himself Emperor after killing Emperor Slakar.
It was unclear what led to the appointment of Lazaroc II as Emperor, but the title clearly became elected. However Lazaroc was usurped by the last living descendant of King Ottak I, Ottak the V. Ottak soon knocked Lazroc from the throne and the title became hereditary once more.