The HK-51 droid, a calculating and ruthlessly efficient assassination machine, in short, the most dangerous machine in the galaxy, will stand by your side and follow your commands in Star Wars: The Old Republic.
“Buried deep beneath the icy surface of Belsavis rests an army of the deadliest, most feared machines in the known galaxy. Thought to have been lost when an Imperial freighter was destroyed, they have recently been rediscovered by a group of renegade Sith Lords. Now both the Sith Empire and Galactic Republic seek to control these dangerous weapons for themselves. Those who are brave enough to venture into the wreckage will emerge with a powerful new ally.”
Check out the introduction CGI trailer to the droid from SDCC last week: