10 Things You Learn Rewatching Star Wars Rebels
3. Kallus Is Everything Hux Wanted To Be
Agent Kallus and General Hux from the sequel trilogy have very similar character arcs. Both initially start in a Grand Moff Tarkin-esque role, commanding large fleets of Imperial/First Order soldiers. Then, their faith in their respective evil organization starts to waver, and by the third season/film in their show/trilogy, they act as spies for the Rebels/Resistance.
While Hux's arc feels rushed, inconsistent, and incomplete, Kallus's results in one of the best characters in Rebels. We spend a lot more time with Kallus than we do with Hux (partially because TV has the added virtue of having more time to spend with supporting characters), and see why he would no longer believe in the Empire. His meaningful friendship with Zeb leads to a brave decision to send the Rebels vital information, which causes him to risk his life even with Thrawn looming overhead.
Meanwhile, Hux only helps the Resistance because he hates Kylo Ren, and survives all of five minutes after his true allegiance is revealed. To make matters worse, his death is very matter-of-fact, and isn't lingered on at all.
Hux's arc doesn't work, but Kallus's shows that it could have, had the Sequel Trilogy devoted more time to fleshing out his character.