While both were highly effective agents of the Empire, Star Wars fans love to debate whether Grand Admiral Thrawn or Darth Vader was the greater asset to the Imperial machine. Their adventures in the Star Wars Legends continuity offer many opportunities to compare the two as leaders, but they also uncover one detail that settles the debate for good.
As a Dark Lord of the Sith, Darth Vader unsurprisingly chose to spread terror to those around him, including his fellow Imperials. Vader’s powers awed and frightened enemy and ally alike, and he frequently employed the dark side power of Force Choke to execute Imperial military officers who he felt were liabilities to the war effort. However, despite his brutal, draconian methods, Darth Vader did not kill every subordinate who displeased him. Admiral Piett repeatedly fails to capture the crew of the Millennium Falcon in The Empire Strikes Back, but he's spared, likely because none of these instances were due to factors within his control, and he’s shown to be an otherwise competent leader. Mils Giel, once an Admiral in the Imperial Navy took responsibility for failing to capture a teezl creature for the Empire, but because Vader saw his admittance as a sign of integrity, he was spared, albeit demoted to lieutenant.SCREENRANT VIDEO OF THE DAY
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Grand Admiral Thrawn shares similar traits to Darth Vader, as exemplified in issue 3 of Heir to the Empire, by Mike Baron, Olivier Vatine, and Fred Blanchard. When Cris Pieterson, a conscripted member of the Imperial Navy, attempts to shift the blame for his failure to capture Luke Skywalker onto his commanding officer, Thrawn executes him on the spot. His replacement, Rejlii Mithel, fails to capture Skywalker with a different method in The Last Command, but takes responsibility for his failure, and is subsequently promoted to lieutenant by Thrawn, who notes his creative thinking.
The key difference between Thrawn and Darth Vader is that, while both earn the respect of many of their underlings while inspiring fear in others, Darth Vader’s decisions are often based on emotion while Thrawn’s are logical. This is fitting, as Darth Vader’s mastery of the dark side requires him to surrender himself to his emotions, but it leads to inconsistent behaviors. While Giel was spared for admitting his failure to Vader, Captain Needa wasn’t so lucky in The Empire Strikes Back, and Vader has slain many under his command simply to express frustration or lash out at the limits placed on him by Emperor Palpatine.
Thrawn and Vader both ruled by fear, even as each was willing to spare those who were clearly still assets to their efforts. However, Thrawn is far more clear-headed about this process, and is even willing to promote those whose failures demonstrate qualities he knows will benefit the Empire later. In contrast, Darth Vader's judgment varies with his temperament, costing the Empire soldiers who might otherwise have risen through the ranks to - ironically - become the next Thrawn. While Darth Vader has the power of the dark side at his beck and call, Grand Admiral Thrawn's more tactical treatment of those he commands makes him by far the better of Star Wars' Imperial leaders.