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

Not brothers, brothers. Ps "It turned out that in the five years of Suntech more than ten years ago, Emperor Duan Lianyi of Suntech was in power in Dali, and North Korea suddenly changed. The emperor was killed by treacherous court official Yang, and then Duan Shouhui, the nephew of the emperor, destroyed the emperor Yang with the help of Gao Zhisheng, a monk and loyal minister of Tianlong Temple. After Duan Shouhui succeeded to the throne, he was called Emperor Shang Ming. Ming Chengzu didn't want to be emperor. After only one year in office, he went to Tianlong Temple to become a monk and passed the throne to his cousin Duan as Emperor Baoding. Emperor Suntech had a father and son, who were called Prince Yanqing in Korea at that time. When the traitor Yang tried to usurp the throne in North Korea, the whole country fell into chaos and Prince Yan Qing disappeared. Everyone thought that he had been killed by Yang. Unexpectedly, after years, he suddenly appeared. The following inferences can be drawn from this narrative: Duan Shouhui is the nephew of Emperor Suntech, and Duan Yanqing is the son of Emperor Suntech, so Duan Shouhui and Duan Yanqing are cousins. Duan is Duan Shouhui's cousin, so Duan He is a cousin. Duan and Duan are brothers, so Duan and Duan are cousins, but it is not necessarily that they are generations. Duan Yu is actually his son, and Wang Yuyan is Duan's daughter. Therefore, Duan Yu and Wang Yuyan are at least four brothers. In the Song Dynasty, according to the clan etiquette of the Han people, marriage was forbidden. But in Dali, customs allow them to form a legal couple. There is a passage in Tian Bu: Mrs. Duan whispered: "Although he (refers to) and your father have the same surname and the same generation, they are not brothers (nor is Mrs. Duan). Your father's daughters, such as Miss Wang, Miss Mu and Miss Zhong, can marry whoever you like ... They may not be able to do DaSong, and they are unmarried and have the same surname. We don't care about this, as long as we are not brothers and sisters. It's very kind of you to get married with these girls. Do you ... do you like it? "