This author is funny. In the original manga, the ottomans are the good guys while the austrians are the evil conquerors. In this manga, the japanese are the good guys while the chinese are the evil conquerors.
@Question2 and you are very naive. In war, there's no such thing as "good" or "bad" guys, war itself is a mistake, so the people who fought in war are neither Hero's or villains, people from both side die, you know? And mind you, this is a fantasy manga, where whatever the mangaka wants to write and draw then that's their world, sometimes have connections with our real world but not in a complete way, because they often romanticize the story. I would suggest you to read more about fantasy and historical manga maybe like how there's many spin-off about Oda Nobunaga, or maybe Arslan, where it also taking historical events as their plot. Maybe that would broaden your view about this kind of manga