R4-G9 was the second Astromech Droid to serve Obi-Wan Kenobi during the Clone War. After the destruction of Obi-Wan's first Astromech Droid, R4-P17, the Jedi Master asked for a replacement droid and was supplied with G9 as soon as the droid left the production line. R4-G9 accompanied Obi-Wan on his mission to destroy General Grievous and flew his starship back home for him to pick up Obi-Wan's giant lizard pet. After Obi-Wan killed Grievous and Order 66 was executed, R4-G9 apparently sided with the Empire and refused to let Obi-Wan back into the ship. Bad move on his part, however, as during the resulting riot by the local natives of the planet, the landing pad containing R4-G9's starship was destroyed, sending him plummeting into the sinkholes below to his death.