The First Order Stormtrooper Executioner is extremely similar to the First Order Stormtrooper. It uses nearly the exact same paint, with only minor differences. There is a black stripe on the far right side of the minifigure's helmet, and both the arms are black. There are also black straps on the corners of the torso mold.
First Order Stormtrooper Executioners were a variant of the Stormtrooper utilized by the First Order around 34 ABY during its conflict with the Resistance. Part of a special branch of Stormtroopers, Executioners were tasked with dispensing final justice on First Order soldiers found guilty of treason.
Owing to the First Order's merciless attitude towards treason, trumping even that of the Galactic Empire where even a derogatory remark was considered treasonous, the First Order stormtrooper executioners tended to do several public executions on anyone with even slight loyalty issues each day. In addition, the stormtrooper executioner underwent several rotations during each session, and was even considered at times a test to see whether they will make it within the Stormtrooper Corps. They were trained to deal with anyone disloyal to the First Order.
Prior to his defection from the First Order, Finn undertook executioner duty, hoping each day would end without having to carry out any executions.
After Finn's defection to the Resistance and subsequent capture aboard the Supremacy, two executioners were brought out by Captain Phasma to execute Finn and his companion Rose Tico, deeming an execution by blaster to be "too good for them". The two selected prepared to dispense justice upon them and prepared to behead them on Phasma's command. Right as she gave the order, however, the Supremacy was suddenly devastated by Vice Admiral Holdo's suicide maneuver when she rammed the heavy cruiser Raddus into the Supremacy at lightspeed. The two executioners, along with the majority of those gathered in the hangar, were killed instantly in the devastation.