C-3PO is a protocol droid whose primary functions are etiquette and translation, making interaction between the myriad races of the galaxy possible. Protocol droids such as Threepio are particularly useful to diplomats like Princess Leia, who must be especially aware of the subtleties of custom and language among the other cultures they encounter. Capable of conversing in six million forms of communication, Threepio is particularly versatile, owing in part to his wide variety of experiences. These experiences have also given him a distinct, pragmatic and pessimistic personality, making him almost human in his perceptions and feelings. Often paired with his spirited maintenance droid counterpart R2-D2, Threepio serves as Artoo's interpreter for human masters. While serving as a diplomatic protocol droid aboard Princess Leia's starship Tantive IV, C-3PO is unwillingly drawn into his counterpart's quest to find Obi-Wan Kenobi.