The Grand Vizier, often referred to as simply Vizier, held the most elevated position in the Galactic Empire's government. This individual presided over both the Imperial Ruling Council and the Imperial Senate, acting as the second-in-command to the Galactic Emperor, Sheev Palpatine. Furthermore, they served as a crucial link between the Emperor and the high-ranking officials within the Imperial Military. Mas Amedda was the sole individual to hold this title, a highly regarded figure within the fascist government.
The establishment of the Grand Vizier's position occurred after the Clone Wars concluded and the Galactic Republic underwent its transformation to become the Empire. Mas Amedda, a Chagrian who previously served as Vice Chair of the Galactic Senate under two Supreme Chancellors, Finis Valorum and Sheev Palpatine, was subsequently granted the title of Grand Vizier after Palpatine's rise to power as Emperor. Having solidified his control over the galaxy, Emperor Palpatine largely withdrew to the seclusion of the Imperial Palace, entrusting the daily governance of the state to Grand Vizier Amedda and attending to matters of the Imperial Senate. In addition, Amedda possessed the authority to govern as Palpatine's representative during the Emperor's absence from Coruscant, the cosmopolitan throneworld.
During the Galactic Civil War, Palpatine's death occurred at the Battle of Endor in 4 ABY, leaving the Empire without an Emperor. As the highest-ranking official in the New Order following Palpatine, Grand Vizier Amedda inherently assumed command of the Empire. Despite this, he struggled to secure any meaningful authority beyond the capital and found himself largely unable to prevent ambitious warlords from fragmenting the Empire into numerous remnants and factions. Nevertheless, even the throne world of Coruscant universally recognized the Grand Vizier's authority, even as it was embroiled in a state of civil war between Imperial loyalists and rebel sympathizers.
Amedda ultimately spent the war's final months as a prisoner held by Fleet Admiral Gallius Rax of the Imperial Navy. Rax, utilizing the Grand Vizier as a symbolic figure for propaganda purposes, declared himself Counselor to the Empire, effectively becoming Emperor while Amedda remained confined within the Imperial Palace. When a group of Coruscanti youths infiltrated the palace with the intention of assassinating the Grand Vizier, Amedda instead persuaded them to rescue him, promising to end the war in exchange for his freedom. Following Rax's demise and the Empire's defeat at the Battle of Jakku in 5 ABY, Amedda signed the Galactic Concordance treaty, officially surrendering the Empire to the New Republic. In return, he received amnesty and was permitted to resume his position as Grand Vizier on Coruscant, albeit in name only. Placed under the supervision of Republic overseers, Amedda became the symbolic leader of a powerless provisional government on Coruscant.
During the era of the Galactic Empire, the Grand Vizier occupied a highly prestigious position, functioning as the de facto leader of the government. Mas Amedda, previously the Vice Chair of the Galactic Senate, held this title during his time as one of the most influential advisors to Galactic Emperor Darth Sidious. However, the office's power diminished due to the Empire's decline and subsequent collapse in 5 ABY. Consequently, the role of Grand Vizier was reduced to a mere figurehead.
In his capacity as chief deputy, the Grand Vizier acted as a mediator between the Emperor and his subordinates. His purview and responsibilities encompassed the authority to summon high-ranking military officials, welcome visiting dignitaries such as governors, and oversee the Empire's bureaucratic apparatus as the head of the Imperial Ruling Council. Furthermore, the position wielded influence over the Imperial Security Bureau, to the extent that ISB agents deviated from their standard procedures based on Vizier Amedda's recommendations. The Vizier's office was situated within the Imperial Palace, the Emperor's headquarters on Coruscant.
Before the rise of the Empire, Mas Amedda served as the Senate's Vice Chair during the Galactic Republic's final years. By the conclusion of the Clone Wars in 19 BBY, Supreme Chancellor Sheev Palpatine declared himself Emperor of the Galactic Empire. Amedda continued to serve Palpatine—who was secretly the Sith Lord Darth Sidious—in the New Order, replacing his title of Vice Chair with the new one of Grand Vizier.
One of Amedda's initial actions as Grand Vizier involved staging a public demonstration on Coruscant, where he proclaimed the end of the so-called tyranny of the Jedi Order and set fire to a collection of lightsabers taken from fallen Jedi.
In 14 BBY, Vizier Amedda informed Moff Wilhuff Tarkin that he would be embarking on a mission to Murkhana alongside the Sith Lord Darth Vader. Around the same period, a group of insurgents commandeered the Carrion Spike, Tarkin's personal starship, and utilized it to attack Galidraan Station. The Grand Vizier, believing that the Empire could not afford to ignore acts of defiance, overturned the Imperial Security Bureau's recommendation to allow the Carrion Spike to escape.
Before the Galactic Civil War, Governor Arihnda Pryce of Lothal journeyed to Coruscant, the galactic capital, to discuss the industrial and mining sectors of her homeworld. Upon her arrival on the city-wide planet, she was greeted by the Emperor's Grand Vizier.
By 4 ABY, Emperor Palpatine's rule came to an end with his death during the Battle of Endor. In the absence of the Emperor, Vizier Amedda attempted to maintain the Empire's cohesion, acting as a proxy emperor. However, the ensuing succession crisis and the concurrent rise of the New Republic further destabilized the Empire, leading to the emergence of numerous remnants and splinter states, while Coruscant descended into rioting and civil war under Amedda's leadership.
Within a year of the Emperor's demise, the Grand Vizier had become virtually powerless as Fleet Admiral Gallius Rax consolidated the Empire's military under his command as Counselor to the Empire. Under Counselor Rax's orders, Amedda was imprisoned within the Imperial Palace and compelled to broadcast propaganda speeches in support of his captor. Following Rax's death at the Battle of Jakku, the vizier was able to sign the Galactic Concordance. In recognition of his role in ending the war, the Republic permitted Amedda to resume his governance on Coruscant as the head of a provisional government. Nevertheless, to ensure that neither Amedda nor his government posed a threat to the new democracy, Republic overseers were stationed on the former galactic capital.