There are multiple interpretations when it comes to translating a Japanese name and anglicising it. Either are acceptable, though the official English translation will take precedence (and is Werner).
If it was your hope that it would continue unhindered (as it was mine), then I regret to inform you that it eventually involves a romantic relationship concerning Werner and a woman, at least in the light novel. Apparently there have been several deviations from the source, but I am doubtful this will be one of them, unfortunately. Ultimately, the author of the LN is also the author of the manga, so they will have that leeway as I understand it to make changes as they wish. In any case, the series is entertaining enough outside of that facet, so I suppose I'll keep reading.