I think that the mini antagonist was more of serving as an example of the situations that Leylin will have to face more often as she carries out her duties as a leader.
tbh it was a dick move for her dad to plan out her fiance when she was only two. And it's her c o u s i n.
And with everyone mentioning the red flags when it comes to the ML and FL's relationship it could be a build up 👀
We can only wait and read
This manga has everything.
A scumbag and disgusting Prince (villain)
A strong and powerful heroine
A Male Lead that has yet to show us his true personality
The age gap is kind of offsetting but as others have said, as long as he keeps it PG until our Lead comes of age, it'll be worth reading