What I can understand is that the young man who just arrived from Ming is the brother-in-law of the young man with the split eyebrow, but they had a relationship together. The sister of the young man with the split eyebrow (wife of the young man who just arrived, but it was a forced marriage) died so he was widowed, but it is forbidden for him to remarry or have affairs. The young man in blue is the crown prince, also the brother-in-law of the young man who just arrived and brother of the other two. The middle brother is married with three children, and the young man with the split eyebrow is single and does not want to get married, probably because he still loves his brother-in-law and is apparently plotting a revolt.
