Soowon s father killed all the hostages when he said he would give them back and there was a friend of the princess among them
But why is SooWon so intent on going to war?
Well, a war can benefit a kingdom - could mean more territory, more power or status.
(+) Yona's father had lost good part of the land to others countries.
I think He explained it not to long ago.. A few chapters back...
Wasn't there sth abt how he had to get that done so he wouldn't have to worry abt it being a threat when there s also that vig threatening country? And that the princess wanted to kill him so much that they would definitely go to war so he thought he should strike first or sth...
It seems that this arc is about revenge concerning Su Won's dad. Something really harsh happened between Princess Kouren and SuWon's dad and SuWon is taking aggressive action because of it. This was the darkest chapter I read since seeing Jeno getting his head cut off and regenerating.