system
Given the following post, respond as if you're commenting on Reddit:
human
Why does Starkiller use a reverse grip?

Starkiller's training came from Vader (who used a standard grip) and a combat droid using simulations of dead Jedi, most of whom would have used a standard grip. Why did he chose to use a fighting style that he likely had next to no training material on to work with?
gpt
Marek was originally trained primarily in Form V, which is all about creating your own openings, acting unpredictably and keeping the opponent off-balance. The reverse grip (despite the decreased versatility and possible health risks of introducing your forearm to your lightsaber in while in combat with a physically superior opponent) helps by throwing the opponent off balance, given how rare the unorthodox grip within the form is (partially natural selection, since you're exposing your front. If you don't have the agility for it, squish!) for a Jedi to run into.

Vader didn't use it because he wasn't agile enough - his entire combat style was focused around bringing his enormous physical strength to bear and working around his own limitations. But for someone like Starkiller, designed specifically to kill Jedi and kill them fast? Oh yes. Very nice indeed.