So, let's get this straight... the elder of the Mauser school of Panzerkunst, the school that specializes in assassination, deep ops, shock troopers, and cover-ups... is the commissioner of the Guntral's internal affairs department?
That isn't convenience... that is plain irony.
Keun just accepted this mission and he almost got caught already, if there is someone that can recognize an undercover agent just by the subtle ways they move is people like Henkel and Gelda... she seemed to not react to him passing but I wouldn't put past Gelda to have noticed him even more than Henkel, but she is good enough to understand why he was in another body in a second.
You know... it could get in the way of the story... but I would love at least a glimpse into the life of Tiger Sauer, the creator of Panzerkunst, we know Caerula saved him as a baby, and we have hints that he was a martial artist to rival even Caerula herself in the technical aspects of it... but the man didn't simply make a new martial art... he created the pillar of a whole nation in a period of "history" that was pure unbridled chaos, the guy must have been a genius tactician and charismatic leader to a scary degree.
Just the fact that another secret organization felt the need to establish itself at the same time and deeply in the heart of his nation, shows that someone even then already knew this guy was special.