While we may think that Dark Troopers are the strongest Imperial droids, they aren’t. KX-series droids are stronger and sturdier because of how they were designed. They also benefit from filming aspects that make them more imposing.
How KX Droids and Dark Troopers Are Built
KX Droids are designed to be stronger than Dark Troopers. As this discussion indicates, KXs are meant to be “an insurmountable threat” while Dark Troopers serve essentially as “scary lightsaber fodder.” This commentary provides an entryway into how each Imperial model is built differently.
As “enforcer droids,” the KX-series security droids are built to be intimidating and to back up their physique with pure strength. Manufactured by Arakyd Industries, the KX-series are designed with “exaggerated human proportions but with the mobility of a human athlete.” They are strong and agile.
Thanks to Andor, we saw these capabilities in full display. In these scenes, which start with the Gorman Massacre, we see these threatening droids decimate anyone in their path. Their power resonates outward from their sturdy, robot-like construction.
Their “masculine programming” and black or “Carboplast” plating color certainly accentuate their destructiveness. KXs are also known to use E-22 blaster rifles, making them even more deadly. It’s not their size and strength alone that make them “intimidating and unsettling to many people, both Imperial and rebel.”
Now, we may also say that Dark Troopers are menacing and threatening, just like KX Droids. Yet, their degree of sturdiness is not on the same level as the KXs. Originating as “experimental soldiers,” these troopers evolved into a more imposing form only after the Empire collapsed.
The Phase I version was a droid with “little more than a skeletal frame equipped with a vibrosword.” This Dark Trooper never even saw combat. By the time of Phase II under the Empire, the threatening potential improved, consisting of “a heavily-armored black and silver body suit worn by a human pilot.” Still, this design pales in comparison to the formability of the KX-series.
The third generation or Phase III Dark Troopers by Moff Gideon posed a tremendous threat to Mando. They are “heat resistant, blaster resistant, and utilize extreme strength.” However, their power was undermined by their slow speed, whereas KX moved quite fast.
Moreover, and returning to the opening point, Luke handled these Dark Troopers like they were child’s play. We can recall how they were decimated, not doing the decimating.
Between the two, KX droids posed a more formidable threat because they were ultimately built to be sturdier and stronger.
Other Explanations
The Reddit forum above also tips us off to filming differences between KX droids and Dark Troopers. Using “matte color pallets” provides a more “solid” and “tough” look. So, how the two are filmed and shown on screen could play into outside-universe explanations.
K2SO was brought to life and given strength by actor Alan Tudyk using motion-capture technology. As write-ups like this one explain, K2 was “a completely digital character based on a real-life performance” to make the sturdiness real in Rogue One.
Similarly, Dark Troopers emerged on the screen through practical and CGI effects. This brief behind-the-scenes video reveals some of the process. They look menacing, but the armor comes off more bare bones, and they appear to be more like expert marksmen. So, through filming, we come away with different impressions.
Discussions about different “tiers” of KX droids also provide some explanation for their strength and sometimes lack thereof. Fans have discussed the differences in “classes” and “rings” near the shoulder used to distinguish KXs. This video draws on that reason to explain why one red-ringed KX was easily blasted away by Jyn Erso, while K2SO and others with yellow rings in Andor were nearly invincible.
Designating the more recently filmed KX droids as indomitable has left a big imprint on our imagination about their prowess.
KX Droids Are Stronger and Sturdier
We walk away from Andor and Rogue One with similar conclusions–KX droids are more formidable because of how they are built and filmed. Dark Troopers are quite threatening too, just not in the same sturdy category as KXs.