K-2SO (Kay-Tuesso), abbreviated K-2 (Kay-Tu) or Kay, is the tritagonist in the Star Wars anthology film, Rogue One. He was a KX-series security droid originally created for use in the Galactic Empire's armed forces. Like all droids, he could survive in the vacuum of space.
At some point, the droid encountered Captain Cassian Andor, a member of the resistance movement—known as the Rebel Alliance—that sought to overthrow the Empire and restore democracy to the galaxy. Andor was able to reprogram K-2SO to serve the Alliance. K-2SO is strong, able to pick up & throw multiple stormtroopers with ease.