Actually, there has been a number of discussions on how historically inaccurate this manga is, and there are a lot of things that are out of place, even the most recent chapters, as the Panzer tank was not built until something like 1936, but we just have to suspend our disbelief and go with it, LOLz. But kudos for noticing. *winks*
Thank(o^^o)
Some things are obvious. Also, I don't think chainsaws (for use outside "medicine") were invented until the early 1900. But Shinigamis are Shinigamis so I give them a pass. But I didn't see many discrepancies in the Noah's Cirus arc.
Another big discrepancy is the "Wolfsschluct" (It was Hitler's training camp) As Hitler was not born until 1899, this is another glaring error, as the word Wolfsschlucht was not used until WWII, nearly 40 years later, Hitler was born 10 years after this manga is set. Seems like those interested in History need to overlook all the problems with timelines here.
Additionally, women were not really allowed to be in any kind of combat position prior to WWII, it is pretty rare to see females portrayed this way (nice but not really accurate - nor were they really allowed to be in command - with a few historical exceptions - females would sometimes disguise themselves as males to enlist though)
I was bored and decided to reread the series, and I noticed something very odd in the first 5 chapters: there is no defined time period. The first chapter has a Nintendo game (seems to be a super nintendo game) and superman, the third chapter has a cellphone (it's a flip phone, but still), and the fifth chapter has an Alien reference. This is the Victorian Era, and none of these things were around a that time.