system
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human
[Star Wars Legends] Why did it take so long for Thrawn to get word of the Empire's fall and return from his campaign?

Wouldn't other imperials have told him, at least to get reinforcements against the Rebellion? Wouldn't he have noticed his supply lines or troop rotations are different?
gpt
He knew of the fall almost immediately but stayed in the shadows for tactical purposes. Thrawn became a Grand Admiral upon killing Grand Admiral Zaarin but this wasn't public knowledge as Palpatine had promoted him shortly before dying on the Death Star II. As far as the Rebels knew they only had eleven Grand Admirals to go after. 

Thrawn built up his Empire of the Hand for the next ten years. He figured the Imperial warlords would wipe each other out and/or get killed by the Rebels/New Republic, which is exactly what happened. 

Now Admiral Daala, on the other hand, was so isolated in the Maw Installation that she didn't know *Tarkin* was dead, much less Palpatine.