Complex sentence: In some cases, the leader may not be the greatest martial artist in the jianghu (and may even be the protagonist of the story) while in other cases, the position of the leader is hereditary.
Split into simpler sentences: In some cases, the leader may not be among the greatest martial artists in the jianghu. The protagonist of the story may also become the leader by coincidence, while in some other cases, the position of the leader is hereditary.