Whats with these Victorian period Mc and us not knowing their true name? Robin Swift? We wouldn't be able to pronounce it. Ciel Phantomhive? Huh, that's his older brother name (all we know is that maybe our!Ciel's name means star in translation). William Moriarty? Apparently, only Sherlock and Louis know his true name (according to manga that is)

I see the pattern here