FN-2003, nicknamed Slip by his comrades, was a Stormtrooper that served in the First Order's FN Corps during their conflict with the Resistance. He, like most First Order Stormtroopers, was taken from his family at a young age to be trained under First Order Captains Cardinal and Phasma. After his basic training was complete, FN-2003 was put into action, fighting for the First Order for the first time during a skirmish against local forces allied with the Resistance. Despite putting up a fight, FN-2003 would eventually be killed by sniper fire and unknowably scare his close friend and fellow stormtrooper, FN-2187, into defecting from the First Order.
During his training in the FN Corps, FN-2003, gained the nickname, Slip from his fellow FN stormtroopers, due to him being considered the worst shot in the Corps. However, despite this, FN-2003 became friends with another weak link in the FN Corps, FN-2187.
After training in the FN Corps for some time, Slip and the rest of the FN Corps would be sent under the command of Kylo Ren to attack a Resistance-allied base on the desert planet of Jakku. During this battle, Slip would be killed by Poe Dameron and would die right in front of his only friend, FN-2187. The blood of FN-2003 would then be seen on the helmet of FN-2187 for some time before he defected to the Resistance.