Lucasfilm has finally confirmed who will play Star Wars' Grand Admiral Thrawn in live-action. Created by legendary science-fiction author Timothy Zahn, Grand Admiral Thrawn was one of the most compelling villains of the old Star Wars Expanded Universe. The only alien to ascend to such a high rank in the Empire, he was useful to Palpatine because of his strategic genius and tactical skill; Zahn modeled the character on Sherlock Holmes, giving him the ability to intuit his opponents' strategies. Although these stories were rendered non-canon (or "Legends") after Disney acquired Lucasfilm in 2012, Thrawn made the jump into a new era in Star Wars Rebels and several new canon novels by Zahn. The Mandalorian season 2 set a live-action Thrawn up as the franchise's next major villain.
https://screenrant.com/star-wars-thrawn-casting-lars-mikkelsen/