Oswald Teseik, Imperial Marshal.
He came from a distinguished Noble House, one of the very few families with immense influence in both the Core Worlds elite class and the military. Especially after becoming Grand Commander of the Galactic Empire's First System Army, he became a leading figure among the Core Worlds aristocracy.
After Trachta, the governor of the First Legion, was implicated in the plot to assassinate Emperor Palpatine and ultimately died, Oswald Teseik won His Majesty the Emperor's trust by firmly retaining control of the First System Army throughout the incident and unwaveringly standing on the Emperor's side.
Thus, after the turmoil ended, Palpatine did not appoint a new governor for the First Legion. Instead, he had Oswald Teseik concurrently serve as governor. This gave him both political and military control over the First Legion, practically making him the Empire's second ruler in the Milky Way Galaxy's Core Worlds.
Later, he was appointed Imperial Marshal. By then, Oswald Teseik had reached the pinnacle of power. Whether among the Core Worlds aristocracy, the military factions, or even within the small circle of twelve marshals, he was unquestionably the leading figure.
Even men such as Dunn Vesex, the King of the North, and Wilhuff Tarkin, the Emperor's confidant, were courteous before him and did not dare show the slightest disrespect.
However, after the Kingdom of Dawn captured Bilbrin Planet and tore open the Core Worlds' outer defensive line, Oswald Teseik could clearly sense Palpatine's distrust of him.
The more critical the situation became, the less someone as selfish and self-serving as Palpatine, someone willing to harm others for his own benefit, was willing to place his safety in another's hands.
Palpatine began interfering more and more in the First System Army's military affairs, even dispatching Dark Prophets to serve as fleet