WARNING: The following article contains spoilers for the series finale of Star Wars Rebels, "A Fool's Hope" and "Family Reunion and Farewell," which debuted Monday night on Disney XD.
If fans expected, or dreaded, for Star Wars Rebels to end with mass casualties, akin to Rogue One: A Star Wars Story, then they were undoubtedly relieved by Monday night's series finale. Oh, there were losses, of course, but primarily on the side of the Galactic Empire. However, that's not to say the liberation of Lothal didn't come at a cost.
When the smoke cleared, and the last Imperial troops destroyed, we know of only three major deaths. The other two remain mysteries that may never be solved.
Beloved Clone Wars veteran CC-5576-39, aka Gregor, was among the longtime allies recruited by Hera in the episode "A Fool's Hope" for a seemingly hopeless mission to liberate Lothal, not for the Rebellion, but rather for Ezra Bridger. When their elaborate plan to eject Imperial forces from the planet took a bad turn with the arrival of Grand Admiral, Gregor sacrificed himself in the effort to restore power to the shields and protect Capital City from an imminent barrage by Star Destroyers.
No one's going to mourn Rukh, the Noghri warrior who served as Thrawn's bodyguard and, time and again, one of the most competent operatives within the Galactic Empire. Seemingly unkillable, Rukh had the tendency to turn up again and again to foil our heroes' plans. He did that one last time in the Star Wars Rebels finale, only to meet his end in a showdown with Zeb, during which he was apparently incinerated (off-camera, naturally) by the shield generators within the Imperial base in Capital City.
As an Imperial official, Arihnda Pryce lived on borrowed time, more likely to be executed for her failures than promoted for her successes. Not that she had many of the latter, mind you, particularly with Grand Admiral Thrawn breathing down her neck. The governor of occupied Lothal, Pryce became the unwitting key to the Rebels' plan to liberate the planet. Lured into a trap, she became their way past security and into the Imperial compound in Capital City. Certain the entire time that their unlikely scheme would be foiled, if not be her troops then by Thrawn, Pryce remained loyal to the Emperor until the very end. Given a chance to save herself, she stayed within the Imperial complex as it was rocketed into the planet's atmosphere and destroyed.