Shen Mei!
Ranked thirteenth in the family.
Her mother is cousins with Mrs. Luo, the wife of 'Secret Sect Boxing' Luo Liang of the Guangling Ten Tigers, and Mrs. Luo has some ties with Cheng Fengxiao's wife and Yan Chuan's master's wife, making her a distant aunt of Yan Chuan's master's wife.
By this calculation, Cheng Wenlong and Cheng Ah Bi should call Mrs. Luo 'Auntie', and Shen Mei is called 'Aunt Thirteen' by them.
Yan Chuan, being Cheng Fengxiao's disciple, naturally followed suit with Cheng Wenlong and Cheng Ah Bi in addressing her as 'Aunt Thirteen'.
In the early years, the two of them got along quite well.
But eight years ago, when Guangling Academy was established, Shen Mei had a falling out with the Luo family, left the Martial Arts Hall, and joined the academy. At that time, she wanted Yan Chuan to join her, but Yan Chuan refused.
From then on.
One became New Faction.
The other Old School.
Their interactions reduced significantly.