I've been thinking about Yuri and first, I thought she was a stupid doll. Now, if she's from the royal family of the enemy's country, it all make sens. She target the heir prince and got around her finger the futur prime minister and the son of the knight captain (maybe more important pawns). She started to destabilize the country by her "naive" suggestions (like disbanding military) in order to make it easier for her country to invade later.
Once married, she'll probably have a baby and kill the second prince and his entire family. But now that Bern is not anymore under her control she need to take out the prime minister (can't control him) and his family.
Quite a sly fox this Yuri (or not, if I'm totally wrong).
Anyway, it's always rewarding to see the MC take down a conspiracy like that. She build with her own strenght all of her business, I would have been quite sad to see it burned to the ground.