The robot serves as part of the Jyn Erso's rogue group that aims to get their hands on the Death Stars 'plan's - the ones used by the Rebels to identify and exploit the weakness found as per the events of A New Hope.
K-2S0 delivers part 'robot awesomeness' and part comedy relief in a similar vein to BB-8 or the two other famous robots that turn up in Star Wars movies.
Alan Tudyk plays the Enforce Droid, K-250 in Rogue One. He's 8 foot tall and is usually addressed as Kaytoo
Tudyk's persona fits this need quite well have demonstrated his comedy bona fides in his roles in Firefly, Transformers: Dark of the Moon, and Death at a Funeral. He's also done a fair bit of prior voice over work, his roles as Mickey in Halo 3: ODST and Zootopia.
The look of K-2S0 is a 'classic' robot look with dark metal, bright eyes suggestive of The Iron Giant. He wouldn't look out of place serving in Jabba's Palace.
The droid was originally an Imperial, and was reprogrammed by his 'mentor'Cassian Andor. Yet something didn’t quite take.“He’s not quite all there,” Tudyk said. “He speaks his mind and says things that could be unsettling. Very honest. If you know any old people, he’s like that.”
K-2S0 quotes:
Place holder post until the movie comes out!