Backstory: When Edward Richtofen ended up as a pony in Equestria, he started recruiting ponies to rebuild Division 935. Trotz Hoofler was one of those ponies.
Trotz Hoofler was recruited do to his technical genius. He is Division 935’s tech/communications officer and primarily works out of Ponyville.
(Apologies for the Pegasus in the background. He showed up just as I snapped the screenshot.)