This book is screaming for an editor.
No, not even that. This book is screaming for a proofreader.
During my rather casual read-through I encountered two typos, one of which should have been picked up by a spellchecker. Normally I wouldn't mind if I found the odd mistake but given that this book is priced pretty much the same as all the other "proper" paperbacks yet has about half the content you've got to wonder what your money is paying for.
But that's not the end of it. The writing is stiff and awkward, and just screams "translation". I wondered if this was the fault of the original author (though given the source's high rating on Amazon Japan I very much doubt that) but it seems unlikely; the translator apparently doesn't even know what "Sir" (the title) is used for. I'm sure decoding all the Japanese text is a very demanding job but it seems to me that the translator never really learned how to write.
Maybe none of this bothers you. If so, bully for you, but this book reminds me of Romance of the Three Kingdoms,
and not in a good way. Yen Press need to get their act together. They did a great job with Haruhi, so we know they can give this series the respect it deserves. Until that happens, I don't really feel it's possible to review this book's content fairly.
P.S. YP, fire whoever made that cover. It's terrible. I appreciate what you were trying to do, but forever consigning the book to the C-list fantasy bargain bin is the wrong way to go.