Although Disney declared the EU non-canon (or 'Legends') shortly after acquiring Lucasfilm in 2012, it didn't take long for Thrawn to make his way back into the canon, with the Grand Admiral playing a significant role in Star Wars Rebels. Thrawn was introduced in 1991's Heir to the Empire, and he was a constant presence in the old Expanded Universe. The character is reminiscent of Sherlock Holmes, a deductive genius who is skilled at outthinking his opponents, and his particular affectation is his love of artwork. He is the only alien to have attained to the rank of Grand Admiral, a blue-skinned Chiss who hails from the Unknown Regions and whose knowledge of that sector of space proved key to the development of the Empire's plans.
Created by legendary Star Wars author Timothy Zahn, Grand Admiral Thrawn is a unique figure in the Empire. After 30 years, Grand Admiral Thrawn is once again key to the future of Star Wars.