The spidery probe droid, which spied on the Rebels on Hoth has an interesting connection to a new character in Rogue One. It looks like K-2SO and the probe droid are distant robot cousins.
The newest and first standalone Star Wars movie, Rogue One, is technically both a sequel and a prequel in the beloved galactic saga, taking place after the prequel trilogy and before the original trilogy. And though the larger context of the films is about the familial relations between the various Skywalkers criss-crossing the galaxy, another kind of mechanical relative has found its way into Rogue One.
K-2SO is the new Imperial security droid that has been reprogrammed to fight for the Rebels in the upcoming standalone movie, but he’s not really supposed to be new at all. In an interview with Entertainment Weekly, Rogue One Executive Producer and Visual Effects Supervisor John Knoll explained that the design for Kaytoo was culled from the other imposing Imperial droids seen in A New Hope and The Empire Strikes Back.
“It’s not the first time we’ve seen an Imperial droid,” Knoll told EW. “Theres the Imperial probe droid and the sort of interrogation droid that these black shells and a kind of sinister, evil-looking character to them.”
It seems Kaytoo is an older cousin of the Viper droid seen searching for a hidden Rebel base on Hoth in The Empire Strikes Back, and a humanoid precursor to the spherical IT-O Interrogator torture droid that Darth Vader uses on Princess Leia to reveal another Rebel base on Dantooine.
This could possibly explain why we dont see security droids like Kaytoo within the Star Wars universe after Rogue One (unless of course Lucasfilm decides to pull another Special Edition and insert CG versions of Kaytoo into shots from the original trilogy). Their lanky yet stately frame might prove to be unreliable in the fight against the Rebels and they’re discontinued after the events of Rogue One for more specialized hover bots like the interrogator and the probe droid.