Greta's treating Yuuri with surprising formality. Of course, a lot changes in fifty years, especially in the nature of a little girl.
Yuuri's acting surprisingly distant about the family, too. That guard he should watch out for is his granddaughter, after all. Even if it does feel strange to have grown grandchildren at the age of twenty-five.
Wolfram's ill...? I hope it's nothing too serious. After all, to a mazoku the aging of fifty years is worth ten years, so he'd still be young. But young people do get seriously ill, and Wolfram does have weak constitution.
Now, how has Shin Makoku fallen apart so rapidly? Or, well, so thoroughly is what I mean. This is set after the last episode, right? So the things have happened and all that? Oh, gee, I don't know how to say it without giving spoilers if it's not! Well, if it is, then you understand what I'm saying. Maybe.
Would the people not follow Greta? Or whoever took Yuuri's place while Greta grew up. Is she the twenty-eighth or twenty-ninth Maou? Did the fragile alliances with the human nations fall apart? Natural disasters? Did Dai Shimaron dispose of their loopy king and got a new one just as bent on world domination, and Shin Makoku has been fighting a hard war for fifty years?
Author's response
Okay, you did it, you got me to post the new chapter ^-^ Anyway, yeah, I can't really answer much here because it would probably give the plot away. I can say that yes, the things in the last episode have happened. Greta isn't in the position you think she is, but you actually hit pretty close to the mark with a couple of your questions. Wolfram's illness is linked to why Shin Makoku has fallen apart like it has. You'll see what I mean (assuming you keep reading, which I hope you do, because I love reviews like this).