This is more than just a story, it's a reminder and a lesson. Sometimes, we initially don't like some things, but then when a certain person comes along and do that stuff with you, it makes you adore and come to enjoy it. Sometimes those things we do, we do not do just for ourselves, but for the moments we live and make with that person you're with. I like to pay my respects to the victims of the Kyoto Animation Arson Attack (it reminded me of it while reading this), you will be missed and continue to be an inspiration to so many people. Lastly, for Fujimoto sensei, I thank you, this was a very heart-wrenching yet beautifully-written story.
You can't expect them to change, although it would be good in your perspective Roselia, they may become vulnerable to various threats surrounding them, I think it would be better if you just prevent Ein from falling after the girl destined to be with crown prince and improve their behavior at a certain level.