Valkorion is easily GALAXY TIER in his manipulations and the ability to influence his subjects:
Many Jedi speculate that it is only Emperor's iron will that prevents the Sith Order from collapsing into chaos as it has so often done in the past.
Taken from Star Wars: The Old Republic: Encyclopedia
NO SITH HAS generated as much curiosity, frustration, and fear among the Jedi as the Empire's dread ruler.
Taken from Star Wars: The Old Republic: Encyclopedia
Now, an absent Emperor and the uneasy peace following the Great War against the Republic threaten to shatter the backbone of the Empire.
Taken from Star Wars: The Old Republic: Encyclopedia
By drawing on his incredible dark powers, the Emperor imprinted his consciousness onto unwitting pawns who would serve as vessels for carrying out his will. Through the eyes and ears of these "children," he could uncover threats in both the Empire and Republic while they were still nothing but whispers. And should the need arise, the Emperor could seize control of his children and instruct them to crush any plot that dared defy his will.
Taken from Star Wars: The Old Republic: Encyclopedia
Aided by his powerful, secretive, and far-reaching powerbase, the Emperor pulls strings across the galaxy to carry out his master stroke - the details of which only Emperor knows.
Taken from Star Wars: The Old Republic: Encyclopedia
The concealed Emperor manipulates and dominates the galaxy with his far-reaching power base: the Imperial Guard, the Hand, the Voice, the Wrath, and the Children.
Taken from Star Wars: The Old Republic: Encyclopedia
THE EMPEROR fears only death. It was this dread that inspired the Emperor to possess beings to serve as the Voice and the Hand, the former to speak his will and the latter to serve as conduits through which he could control his Empire. To extent his reach and sight, the Emperor created his Children through which he could see and act on whim. For those who displeased him, the Emperor shaped the Wrath - the ultimate executioner, who lived only to strike down enemies of the Emperor and humble the galaxy. Finally, he forged the Imperial Guard as an army of devoted warriors, tasked with overwhelming the Emperor's foes and protecting his domain. With this power base, the Emperor seeks to shield himself from the dangers of mortality and make the galaxy bow before him.
Taken from Star Wars: The Old Republic: Encyclopedia
NOTE: Only the Wrath was an independent actor - by design - the rest were either pawns bind to his will or manifestations of the Emperor himself.
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The aforementioned manipulations do not account for Valkorion's influence extending to the Empire of Zakuul.