The present era is called the Hong Li Federation. But one hundred and fifty-six years ago, this land was a vast empire.
The Hong Li Empire, the empire was divided into two periods, a monarchical system in the early days and a constitutional monarchy later on. The Dawn Revolution marked the dividing line between the two.
After that revolution, the Hong Li empire was no longer ruled by the royal family, but became a form of power divided among the king, the prime minister, and the council. It achieved a de facto republic, while nominally not being a republic. A greater revolution occurred later on.
The royal family disappeared completely.
The Hong Li Empire became the Hong Li Federation.
This is the change on the timeline. Since Casio has the ability to look back at the past through antiques, he naturally needs to understand some of this knowledge, such as the customs and power situations of the era he is about to look back, as well as changes in language.