From my Korean drama knowledge, they had crush on their older brother"oraboni" sometimes and wanted to married them.sometimes they r from different mother.
As it’s our BL story, that's might happen
On other note, it might not love or crush.
We can't Imagine sometime what are obsession do to human. Obsession leads some unimaginable doings.this might happening here.The king is obsessed over his younger brother and long for his trust and support like befor.as he become king by riots, there is no one actual his won.So, he want at least his wom brother beside him for his won. We can imagine how lonely and dangerous it is for the king
As it’s our BL story, that's might happen
On other note, it might not love or crush.
We can't Imagine sometime what are obsession do to human. Obsession leads some unimaginable doings.this might happening here.The king is obsessed over his younger brother and long for his trust and support like befor.as he become king by riots, there is no one actual his won.So, he want at least his wom brother beside him for his won. We can imagine how lonely and dangerous it is for the king