R2-D2

R2-D2, sometimes spelled as Artoo-Detoo and simply known as Artoo is a droid that belonged to Padmé Amidala, Anakin (later Luke) Skywalker and one of the main characters to have appeared in all seven Star Wars films. He was also the counterpart and companion of C-3PO, a protocol droid.

The Phantom Menace
Artoo first appears with his fellow droids by fixing the spaceship that held Queen Amidala. The queen showed its gratitude by having her "handmaiden" Padme Naberrie, secretly the Queen in disguise clean him up. Artoo also went with Qui-Gon, Jar Jar Binks and Padme to find parts for their ship. He also meets his future friend, C-3PO, who was created by Anakin. Artoo later is Anakin's droid guide during the Battle of Naboo.