Blue Four functioned as the callsign for the fourth pilot belonging to Blue Squadron, a squadron of starfighter pilots.
At the Battle of Ryloth, the clone trooper pilot known as "Kickback" operated under the designation Blue Four. He was among the minority of pilots who made it through the conflict alive.
Barion Raner, a pilot fighting for the Rebel Alliance, held the position of Blue Four around the period of the Battle of Scarif.
During the Battle of Jakku, the callsign was utilized by a member of the New Republic's 77 Squadron, which fought as Blue Squadron in that engagement.
Pallaris Ven, a Resistance pilot, piloted as Blue Four alongside his astromech droid BR-BA and met his end during the Battle of Starkiller Base.