Complex sentence: Prince Gwanghae, son of a concubine, usurps the Joseon throne from his father King Seonjo's direct bloodline; he executes the favored legitimate son, and exiles his half-sister Princess Jeongmyeong.
Split into simpler sentences: Prince Gwanghae, son of a concubine, usurps the Joseon throne from his father King Seonjo's direct bloodline. Gwanghae executes the favored legitimate son, and exiles his half-sister Princess Jeongmyeong.