Previous rumors about the character of K-2SO, who will be voiced by Alan Tudyk, are that he is actually a former Imperial droid who was captured and reprogrammed by the Rebel Alliance. While the profile of the character in Entertainment Weekly doesn't make any reference to this, it may still be accurate, as being a former Imperial may explain why Gareth Edwards says this droid can actually be a bit of a jerk
Kaytoo is a little bit like Chewbacca's personality in a droid's body. He doesn't give a shit about what you think. He doesn't fully check himself before he says things and does things. He just speaks the truth.
Needless to say, C-3PO this ain't. K-2SO looks to be a significant change of pace from the perpetually terrified C-3PO that we're used to seeing in the Star Wars saga. K-2SO sounds like he's much more antagonistic. Based on the images we've seen of the character, he is significantly larger than the human characters, which may have the most to do with comparing him to Chewbacca. We're not sure we'd say that Chewie "doesn't give a shit about what you think," he might be able, and willing, to tear your arms out of their sockets, but he does care about his friends.
If anything, this description makes K-2SO sound a lot like HK-47, the droid from the old Knights of the Old Republic video game. He was overly honest to the point of insult, and also hyper violent.
In the history of the Star Wars saga, the droids have been some of the most interesting and fun characters. This has us quite excited to learn more about K-2SO, the new droid companion of Rogue One: A Star Wars Story. While you might expect the bipedal droid to be similar to our favorite protocol droid, C-3PO, director Gareth Edwards, says that's only his outward appearance. His personality bears a much stronger resemblance to Chewbacca.
It doesn't sound like K-2SO is entirely heartless, however. His involvement in the film's mission is apparently a journey of redemption for the droid, as it is with lead character Jyn Erso (Felicity Jones). It seems the droid regrets some past bad actions, which may mean that K-2SO wasn't reprogrammed by rebels, but chose to join them. This is a very interesting consideration which could make K-2SO one of the more fascinating parts of the ensemble cast. We'll learn more this December.