M4-1S
M4-1S functioned as an astromech droid throughout the Galactic War, a conflict fought between the Galactic Republic and the reconstituted Sith Empire.
Behind the scenes
As a present for Star Wars Day beginning May 4, 2015, every player of Star Wars: The Old Republic received the M4-1S Astromech Droid via their in-game mailbox. Its initial reveal occurred during a livestream event focusing on Game Update 3.2.