C-3PO: The Neediest Droid Ever

C-3PO, (often shortened to Threepio) is a fictional character from the Star Wars universe, who appears in both the original Star Wars films and the prequel trilogy. C-3PO is one of the few characters to appear in all six of the Star Wars feature films, and one of the very few to be played six times by the same actor. In all his various appearances, he is portrayed by Anthony Daniels.

C-3PO is a protocol droid designed to serve humans, and boasts that he is fluent "in over six million forms of communication". C-3PO is generally seen with his long-time counterpart, R2-D2, a small, quirky astromech droid. Threepio's main function as a protocol droid is to assist with etiquette, customs, and translation so that meetings of different cultures run smoothly. In his time, C-3PO loyally served over forty masters. He hated adventure and space travel, as they often resulted in him coming out on the wrong end of a fight, losing parts, and having them reattached, sometimes incorrectly. Together with his fellow droid R2D2, Threepio played a vital and pivotal role in the galaxy's history, however lowly he thought of himself.

(...from Wikipedia)

Anakin Skywalker (creator)
Shmi Skywalker
Cliegg Lars (through marriage)
Padmé Amidala
Captain Raymus Antilles
Jost Ellon
Lott Kemp
Vik & Nikki Idd
Ambassador Zell of Majoor
Zevel Hortine
Thall Joben
Doodnik
Jann Tosh
Mungo Baobab
Governor Wena of Kalarba
Unknown junk dealer
Pitareeze family
Captain Huba (theft)
Nak Pitareeze and family
Harthan
Zorneth
Stigrit Krax
Larka Nimondro
King Gokus
Van P. Quist
Prince Jagoda
Royal House of Alderaan
Captain Raymus Antilles
Owen and Beru Lars
Luke Skywalker
Jabba Desilijic Tiure
Luke Skywalker
Leia Organa Solo