What is the relationship between Baili Shouyu and Baili Xuance in Glory of Kings?

What is the relationship between Baili Shouyu and Baili Xuance of Glory of the King

In a small town beside the Great Wall, the two Baili brothers depended on each other. Although their lives were dull, the two brothers The child takes good care of himself. Baili kept his promise and put Xuance's little doll on the table, "This is Xuance." His brother's droopy ears suddenly stood up, he put the doll in his hand on it, and answered in a sweet voice: "This is It’s my brother”