Sonia's mom is the witch that saved the country. But no, actually she's the witch that plotted to seize control of the country. But no, she ACTUALLY planned the war out to mitigate the losses to the country. But no, she really worked with the prince to overthrow the evil king. But no, she actually just wanted to get rid of a rival and steal her research. But no, actually... (not gonna spoil this one and beyond)
they're not human (Sonia, Bill, Emelda, a lot of fathers, etc.)
Seriously, almost everyone ends up dead (pretty much all the fathers now that I think about it), effectively dead (Emelda, Rain, a certain "comrade", or grieving (maid, queen, merchant, etc.) in the end.
I'll note that very early on Mine becomes extremely depressed and contemplated suicide, so for anyone bothered by that sort of stuff I'd avoid chapter 24. It's short and is done mostly to illustrate just how much of a toll Mine's constant failures have taken on her, but it's there.
Despite how things may seem early on, magic actually exists in the world. As the story progresses magic actually becomes a very important plot point. At first it's only important because it's the source of Mine's illness. But as more nobles get involved magic becomes increasingly relevant.
Chako/Yui, Chako is the gender bender in the tags and a guy as revealed at the end