Complex sentence: He always seems to be unfairly treated by his father, King Seongjo, however his father reveals that while Yang Myung is still his beloved son, he is treated harshly to protect Lee Hwon.
Split into simpler sentences: He always seems to be unfairly treated by his father, King Seongjo. However his father reveals that while Yang Myung is still his beloved son, he is treated harshly to protect Lee Hwon.