I don't have to spraypaint everything I see. Just astromechs with monotonous color schemes.
In 13 ABY, he actually joined the Rogues as a temporary replacement pilot while the squadron's senior staff were on Adumar. Because he came from a world the Rogues had liberated, he was extremely enthusiastic and had a general case of hero worship for most of the squadron's pilots. He was also known to be a practical joker, occasionally causing minor inconveniences for the other pilots. Because of the death of another pilot during his first tour of duty, Dorian was offered the chance to remain with Rogue Squadron permanently. A year later, after the Vengeance campaign, he was promoted to Lieutenant.
Dorian remained with Rogue Squadron after the truce with the Empire, accepting promotion to Captain and moving up in the flying order from Rogue Twelve to Rogue Three. He continued to serve with Rogue Squadron until the Yuuzhan Vong war, where he was killed in action at the Battle of Dantooine. He had 79 confirmed kills at the time of his death, including two coralskippers during early engagements with the Yuuzhan Vong.
In order to honor him after his death, many of the Rogues painted big yellow smiley faces on top of their astromechs, referencing one of Dorian's early practical jokes in which he redecorated the R2 unit of a female pilot he fancied. She took the joke well, renaming the astromech "Smiley" and continuing to fly with it until she died alongside him at Dantooine.