R4-I9 was an Astromech Droid and the identical droid brother of R4-D6. Originally he was the exact same color as R4-D6, but when a series of failed relationships (and even one of his girlfriend droids stolen by his brother) and 3 years of ridicule at Alderaan Highschool, R4-I9 became disconnected with the rest of the astromech society and decided to go Goth. The first thing he decided to do was repaint his chassis from his twin brother's blue to a dark and emotionless black. He then dropped out and roamed the galaxy trying to find work. For a short time he was a bouncer droid at a nightclub in Coruscant, but his all black paintjob making him hard to see and lack of any motivation made him a horrible canidate for the job and the manager finally got mad and fired the useless droid. While wandering the streets that night, R4-I9 saw a poster for for the Empire and decided to join. He was instantly accepted because he was already painted all black and basically had a non-existant personality. The fact that he was ready to die and embrace death like all Goths helped too.
When Grand Moff Tarkin had Princess Leia aboard the Death Star, R4-I9 suggested to blow up Alderaan to get back at all the droids and jerkoff people who made fun of him all those years in highschool. Since everyone basically didn't care about R4-I9's opinion, they ignored his idea. But then they thought about it and figured out that Alderaan was basically a planet full of hippies, they decided to blow it up, mainly because Tarkin hated hippies. R4-I9 got no credit. At all. Mainly because he was Goth and everybody on the Death Star hated Goths and their crappy music. When the Battle of Yavin occurred, R4-I9 got to see his brother one last time when an X-Wing was tractored beamed into the Death Star. He was just about to show his brother all of his (non-existant and made up) accomplishments when Luke Skywalker blew the Death Star up, along with R4-I9 and his brother.