The Moon family always had the rule that the family heir chooses the spouse of the other family members of the same generation, such as siblings and cousin. The rule was formed to make sure the others don't try to overthrow the heir. It was followed for more than centuries, and it was started during a king's region after a long hour of requesting the King.
The Moon family has respect among the society majorly because they still followed the family tradition wholeheartedly. It gave them influence to an extent in the upper circle even though they were not as rich as other great families.
