Before long, Thrawn attained command of an Imperial Star Destroyer, the Vengeance.

The Chiss's loss became Palpatine's gain, and despite a strong policy against non-human officers in the Imperial Navy, Thrawn ascended the Imperial ranks. Returning to Csilla, Thrawn was reprimanded for his hostilities, and eventually, his activities caused him to be altogether banished from the Chiss. Thrawn completed the mission that Doriana failed and destroyed the Outbound Flight project. He outlined his mission – to destroy the incoming Outbound Flight vessel – to Thrawn, spelling out the threat that this vessel filled with Jedi Masters posed to the Chiss people. The two conversed, and Doriana was able to appeal to Thrawn's cool sense of logic and order. The taskforce's commander, Kinman Doriana, asked Thrawn for a parley.

The young blue-skinned commander was able to decimate the intruders despite inferior weapons and numbers. The rest of the galaxy made first contact with the Chiss when a taskforce dispatched by Palpatine stumbled upon Thrawn's fleet. His tactics were controversial in their boldness, and his activities within the Chiss Expansionary Defense Fleet drew many a concerned, glowing red eye. Recognized long ago by his people, the Chiss, Thrawn's greatest weapon was his mind. A consummate strategist, Grand Admiral Thrawn likened combat to art and was an aficionado of both.