Wex "TIE-Die" Dafid held the rank of commander within the Alliance to Restore the Republic. He functioned as the tactical training officer for Starfighter Command. His base of operations was the Mon Calamari Star Cruiser known as Independence, during the initial stages of the Galactic Civil War. Before becoming an instructor, Dafid served as a pilot, undertaking 150 combat missions for the Alliance. These missions resulted in a three-inch scar on his face and the replacement of a missing hand with a mechanical prosthetic. His experiences gave him a strong understanding of tactical flying, which helped him as an instructor, but his appearance and intense demeanor often made his trainees nervous.
Before becoming a training officer, Wex Dafid was a pilot who flew 150 combat missions with the Alliance to Restore the Republic. During the early Galactic Civil War, the recruits he trained knew very little about Dafid's early career with the Alliance. According to rumors among the rookie pilots, he had broken almost every rule of combat and nearly got killed many times. These stories, whether true or not, explained his three-inch facial scar, his mechanical hand, and his nickname, "TIE-Die."
By 1 BBY, Dafid, holding the rank of commander, was the main tactical training officer for Starfighter Command on the Mon Calamari Star Cruiser Independence. His office was located near the ship's simulator room. Dafid oversaw the training of numerous recruits, including Keyan Farlander and Sunnar Jan-lo, who were Agamarians. He put them through simulated missions and taught them the skills they would need to survive in combat. Pilots were rarely allowed near an actual starfighter until they had successfully completed every training scenario to Dafid's standards. Keyan Farlander was an unusual case, as he was sent to active duty on the orders of General Jan Dodonna after achieving almost perfect simulator scores, even though Dafid didn't think he was ready. After completing Dafid's training, pilots often served in one of the Independence's squadrons, though some were later assigned elsewhere. Dafid also retrained pilots who had shown weaknesses in specific skills, in addition to training new recruits.
Dafid was a stern and serious officer. He was rumored to have learned the value of proper tactical flying from his early combat experiences. His intense personality, combined with his facial scar and mechanical hand (the strength of which he often misjudged), often intimidated young recruits. When he first observed Farlander's class, carefully examining each pilot while muttering to himself, Farlander's initial impression was that Dafid was crazy. However, Dafid was a skilled instructor who cared about the well-being of his trainees and was determined to ensure they were prepared before sending them into combat. Each training mission was designed to teach a specific lesson, and Dafid didn't care how many attempts it took trainees to complete them, as long as they demonstrated a full understanding of the lesson. He usually addressed his pilots by their last names, only calling Farlander by his first name after the pilot was promoted from his class. He had a sense of humor, but the intimidated recruits in his class rarely laughed at his jokes.
Rusel DeMaria created Wex Dafid for the 1993 book X-Wing: The Official Strategy Guide. The book told the story of Keyan Farlander, the player character in the game Star Wars: X-Wing. Dafid is presented as the tactical training officer on the Independence while Farlander is in training. However, in the game, Farlander's tactical training takes place at an EF76 Nebulon-B escort frigate that serves as a training center, away from the Independence, and General Dodonna gives the scenario briefings.