R0-4, alternatively known as R-Zero-Four, functioned as a protocol droid and held the position of secretary for Koth Melan on Bothawui, the Bothan planet of origin. His exterior, crafted from metal, possessed a radiant, golden sheen due to meticulous polishing. In accordance with the typical behavior of protocol droids, R0-4 exhibited a tendency towards excessive literalness and a knack for creating awkward situations.
During the occasion when Dash Rendar and Luke Skywalker arrived at Koth Melan's location to deliberate on the communication dispatched to Leia, R0-4 prevented their entry due to their failure to meet the criteria of either being Leia herself or possessing a pre-arranged appointment to meet with Melan.
Recognizing the futility of their current approach, Dash aimed his blaster at the droid and presented himself as the "Man with a Blaster About to Cook You." Subsequently, R0 facilitated their access to Koth.