Whilst holding a break from the main Japanese translation comparisons, I thought it'd be interesting to take a glance at how European translators handle the title of the monarch himself.
This shall be done in brief notes going through the various terms with a short explanation or remark upon anything of interest.
Kejser (Keiser) - The Emperor:
The Danish word for emperor is "kejser", literally taken from the cognomen of Gaius Julius Cæsar - whose own dynasty would bring about the rulers that would etymologically inspire names to various imperial titles of Europe, such as the Russian Tsar. The cognomen itself is of nebulous origins, but some point towards it literally meaning "the hairy one." Thus the grand rulers of vast empires were in fact hirsute monarchs, nominally speaking.
The English word, in turn, stems director from the Latin imperator referring to the commander-in-chief of the armies and following Cæsar's death and the succession of his heir Octavius, he amassed to himself several titles of office, one of which was imperator, to refer to his role as the chief executive of the Roman armies. This later became merely one facet of the Roman emperor's authority and as such the word developed across various European languages the sense of "monarch ruling over several territories other than his own local one," and as such we see the Romance languages sporting empereur (French), emperador (Spanish) and so on.
Charles the Great had his Latinised own forename Carolus rendered into the local word for "ruler" in chiefly Slavic languages such as Polish in the guise korol where it means "king." His own name literally means "man" or in this case "freeman," the English cognate to this ancient Germanic name is "churl" with the not-so-flattering sense of "rude fellow" or even "boorish/uneducated ruffian."
These three etymons will figure prominently in the translations as we shall see of the Emperor's office or demotion of office.
I have used translations freely available through Wikipedia as the basis for my analysis in this article.
Russian: korol (король)
French in the Wikisource version opts for demoting the Emperor to the office of archduke, thus His Highness apparently was unfit for the high office of the Andersen original, likewise the Russian version has him as a king (korol) rather than an emperor or even Tsar, which is the case for the origin of the respective words for "emperor" in Polish and Czech versions - not that they are outright calling the Andersen Emperor a Tsar, but rather that he is a nameless emperor. The other languages keep his title.
What then of the honorific styles?
Vaše Veličenství (1), Vaše Císařská Milost (2)*
Your Majesty (1), Your Imperial Grace (2)
Euer kaiserliche Majestät
Your Imperial Majesty.
la Maestà Vostra
jego cesarska mość
His Imperial Grace.
<nothing = We are most disappointed!>
The king is merely referred to by either the third person masculine pronoun or simply "King."
ers kejserliga majestät
Your Imperial Majesty.
*I have used two translations for the Czech version, thus the numerals denote these as they appear on the Wikisource pages.
French once more drills it into the reader that the ruler is a mere archducal noble - not like his international translational royal and imperial peers.