Star Wars Theory: We May Already Know How Thrawn Will Die On Ahsoka
Once the Rebel Alliance took out Palpatine (Ian McDiarmid) and his Empire at the end of "Star Wars: Episode VI: Return of the Jedi," there was no telling what would be coming next. Fans could theorize all they wanted, but Lucasfilm ended up approving the Legends novel series the "Thrawn" trilogy. The books by author Timothy Zahn showcase Grand Admiral Thrawn's campaign to overthrow the New Republic, which eventually ends with his death at the hands of his own bodyguard, Rukh. This may give us an idea of what to expect on "Ahsoka."
Of course, it doesn't have to be the character's bodyguard who betrays him, and with Rukh not existing on the series as of yet, it means someone else would have to do the deed. While the series lead, Ahsoka (Rosario Dawson), would be the natural choice to take out Thrawn (Lars Mikkelsen), the search for Ezra Bridger (Eman Esfandi) could put any one of the protagonists in a position to kill the Grand Admiral. However, there are some more logical choices if the showrunners want to pull from the source material.
Why it should be Skoll or Hati
What makes Thrawn's death in the novels compelling is not that he is taken out by the end of the trilogy — he is the villain, after all. It's that his cruelty and nefarious behavior cause him to make an enemy of one of his allies. Rukh uses Thrawn's own knife as a weapon against him in response to the Empire's enslavement of his people and the continued destruction of his homeworld.
If series creator Dave FIloni wants to follow in the footsteps of the trilogy that chronicles the Thrawn campaign, then he would need to lean on the idea that Thrawn will be betrayed by someone intimately close to him. Baylan Skoll (Ray Stevenson) is the most obvious choice since he's the one doing the Grand Admiral's bidding across the galaxy, but he could turn against Thrawn if the Grand Admiral eventually starts pushing the boundaries of his moral code.
The other obvious choice to take out Thrawn is Skoll's apprentice, Shin Hati (Ivanna Sakhno). While Skoll is a former Jedi Knight and could be swayed by his teachings the way Darth Vader is in the end, Hati is more unstable and could end up betraying everyone in the pursuit of her own nefarious ends. Don't be surprised if she takes out Skoll and Thrawn in one swift move.