Imperial espionage droids were special Imperial droids manufactured by Cybot Galactica. Designed to look and function like standard protocol droids, they were sold to individuals under investigations, where their special transmitters enabled them to relay important information to Imperial Intelligence units.
In 3 ABY, the protocol droid known as K-3PX stationed on Gamandar reported directly to Darth Vader on the actions of Admiral Griggor Tower, who had just launched a destructive attack on the planet Iskalon. K-3PX then led a contingent of stormtroopers into the detention block where the Admiral was interrogating the captured Lando Calrissian and Chewbacca, and relieved Tower of his command, placing him under arrest. The stormtroopers obeyed K-3PX's orders without question or hesitation.
- Star Wars Customizable Card Game – Hoth Limited (Card: R-3PO (Ar-Threepio))
- Star Wars: Rebellion: Prima's Official Strategy Guide
- Rebellion Era Campaign Guide