Gilad Pellaeon

Gilad Pellaeon was a Imperial Military officer in the Galactic Empire Imperial Navy who later became Head of State of the Imperial Remnant and achieved the rank of Grand Admiral.

As the captain of Chimaera, Pellaeon was Grand Admiral Thrawn's flag captain during the latter's campaign against the New Republic. Pellaeon often questioned Thrawn's tactics, but he learned much from the Chiss Grand Admiral and regarded him as a mentor.

In later years, Pellaeon had become the head of the Imperial Remnant and signed the Pellaeon-Gavrisom Treaty that brought peace between the Remnant and the New Republic.

Formation of the Remnant
This information has been taken directly from the Star Wars Databank (located here)

Pellaeon was successful in reaquisitioning Chimaera at the Battle of Gravlex Med, which he had repaired and made it his flagship. Around that same time, the Moff Council recognized his merits and successes, promoting him to the rank of Fleet Admiral and making him chair of the council. Now an aged and rather wise commander, Pellaeon at last showed that he was indeed Thrawn's pupil when he decided to withdraw from an obvious defeat and proposed an to end to all hostilities between the Galactic Empire and the New Republic. He further showed the knowledge he had acquired from Thrawn when he allowed subordinates, such as Captain Ardiff, Chimaera's commanding officer, to question his judgment without punishment, much as he had to the Chiss Grand Admiral. Despite his position, however, there were those who did not want peace. Among them was Disra, Moff of the Braxant Sector, who devised a plot to have a con-man play the part of Thrawn in order to take control from Pellaeon. The plot, though well planned, was quickly foiled by agents on both sides of the conflict, eventually ending in Pellaeon signing a treaty of peace with the New Republic's acting Chief of State Ponc Gavrisom aboard Chimaera in 19 ABY, bringing to an end the Galactic Civil War fifteen years after the Battle of Endor. Sometime afterward, in recognition for his duty and loyalty to the Empire, the Moffs elevated him again, this time to the rank of Grand Admiral.

Retirement
Under the leadership of Pellaeon, the Remnant maintained an isolationist stance and prospered and developed under his five year position as the Head of State, he succeeded in stablizing the remains of the Galactic Empire into the modern Imperial Remnant, expanding the good portion of his forces which were lost to the New Republic. Eventually he retired from service, finding that he had laid the foundation for a new Empire to resume being constructed and grow upon. After Supreme Moff Lucious Sevrus assumed the role as leader of the Remnant, he has voiced his support for the ambitious and progressive politician, commending his approach in rebuilding the government and bringing both the Remnancy and New Republic closer together.