What's the relationship between paragraph and sum in Dragon's Eight Branches?

According to Jin Yong's novel Tian Long Ba Bu, they are brothers of the same race. Duan Yanqing is a former prince. Due to the civil strife in Dali, his father's loyal German emperor Duan was overthrown by the powerful minister Yang, so he was in trouble. Later, Yang was killed, and Duan Shouhui, the nephew of Duan Lianyi, ascended the throne and was called the Emperor of the Ming Dynasty. Later, he abdicated and passed the throne to his cousin Duan Zhengming, who was the emperor of Baoding. Duan is the younger brother of Emperor Duan of Baoding, so he is also a brother and sister.

Another relationship, unable to escape from Tianlong Temple, met Duan's original wife, Dao Baifeng, who hated Duan's philandering. In a rage, she committed herself to being covered in scars and disheveled, in retaliation for Duan. After pregnant with Duan Yu. From this point of view, they are rivals in love, but Duan didn't know it until the moment he died. This is a novel.

As for the official history, Duan Lianyi had no children, so he later made Duan Shouhui emperor. Due to the serious lack of Dali historical materials, the name Duan Yanqing has only appeared sporadically twice in the history books, and the specific identity is unknown. Jin Yong borrowed this name and said that he was the son of Duan Lianyi. Incidentally, in the official history, Duan did not die before his brother Duan as in the novel, but proclaimed himself emperor after Duan and passed it on to Duan Yu.