Royal blue

France and Britain are often away from the castle and their kids, the English siblings were raised by maids and servants, Canada was taught how to be a true leader so he didn't have much of a childhood, and America just being the backup prince took his time to goof around the castle avoiding his limited responsibilities, Australia the oldest and at one point only daughter took a liking to the knights and would often sneak off from her studies to watch them train, wishing to be the head of the royal guard, Nz once a young boy took a liking to the arts and whatever study the library could offer, now shes a well-educated princess still eager to learn more.

As for the Slavic family, R.e the father was a religious man raising his children to respect the church, Soviet the oldest actively rebelled against this idea doubtful of gods ability to run a nation he spent his time learning how to properly run a nation, while Russia the second oldest took care of his siblings and when he wasn't he spent his time at the church or studying in the library however if you were close with him you could definitely say he was a respectable and friendly person despite coming off as cold and intimidating.

This is a love story involving both kingdoms, and this love story starts as many do with an elegant ball filled with royals and nobles from every corner of the world.