FN-2187 wasn’t the first stormtrooper to escape Imperial ties and fight for a greater cause. At least, not if you count this fan-favorite legends character.
Kyle Katarn’s journey to becoming a master of the Force was not a typical one, even in Luke Skywalker’s era of training Force-sensitives following the Battle of Endor. Katarn’s story began not long after the Empire did, and he spent many years pulled between the dark and the light.
He went from stormtrooper to mercenary to Jedi Master throughout his lifetime. But unlike many eager Force-sensitives curious about the Force even at an older age, Katarn resisted Luke Skywalker’s training in the beginning because of his fear of the dark side. He would face its temptation more than once preceding and following his Jedi training.
Some of his backstory would have to change if brought to canon: He played a major part in getting the first Death Star plans to the Rebel Alliance, which has now been rewritten in Rogue One. But old-school Star Wars video game fans wouldn’t mind seeing him appear once again.
There’s not a great chance he’ll make an appearance in Star Wars Episode IX. But the upcoming live-action series seems like a good fit for his character, since he joined the New Republic era in the original legends storyline.