Thrawn

Thrawn (born Mitth'raw'nuruodo) is a major villain in the Star Wars universe. He was ntroduced in the 1991 Timothy Zahn novel Heir to the Empire, being Commander of the Galactic Empires remaining forces after the defeat if Palpatine at the hands of his former Apprentice Anakin Skywalker (Darth Vader), where he faced off the Skywalker twins, Luke Skywalker and Leia Organa Solo. He is seemingly resurrected in the Hand of Thrawn duology (1997–98), and his backstory is explored in various other novels, short stories, comics, and video games in the Star Wars expanded universe. Due to his popularity in the non-canon legends, he was introduced in the new Star Wars Canon as the main antagonist of the third and fourth and final seasons of Star Wars Rebels television series.

In the Legends material, Thrawn was voiced by Tris King in TIE Fighter and Robin Atkin Downes in Empire at War: Forces of Corruption (who also voiced Cham Syndulla in the Clone Wars and Rebels television series). In canon, he was voiced by Lars Mikkelsen. In both Canon and Legends continuity, he is voiced by Marc Thompson in the audiobook versions of both the Legends and Canon Thrawn trilogies.

Season 3
Annoyed by the recent rebel activity going on at Lothal, Arihnda Pryce approaches Grand Moff Tarkin and requests for the assistance from someone who sees a "bigger picture" about bring about the downfall of the rebels and requests for the Seventh Fleet led by Grand Admiral Thrawn. While some officers, such as Konstantine, believed that these ships were the rebel fleet, Thrawn and Pryce actually both believed that this group of rebels were the key for the Empire to destroy the Rebellion before it begun. Pryce revealed Thrawn just didn't want to concern himself with just Phoenix Squadron, but the Rebel Alliance as a whole.

Season 4
In the series finale, Thrawn returns from Coruscant, ruining Ezra an his friends' plan in liberating Lothal from the Galactic Empire. he is contacted by Ezra, who confidentially tells Thrawn that he and the rebels have taken the Imperial dome prisoner. However, Thrawn is revealed to be one step ahead of them and instead will only accept the young Jedi's surrender. When Ezra refuses, Thrawn orders a planetary bombardment and had sent Rukh to cause the rebels' shield generator to malfunction. unwilling to see his people suffer, Ezra is coerced into giving into Thrawn's demands. Ezra takes Thrawn into hyperspace, with the assistance from the Purrgil, to free his homeworld of Lothal.

Hera Syndulla
They first encountered each other on Hera's homeworld, where there was immediate animosity between the Twi'lek freedom fighter and Imperial Grand Admiral.