In the finale chapter, because the time span is very large, Xiaoyu wanted to write a little sense of vicissitudes of life, so the characters were slightly blurry.
That old shepherd slave was a refugee in the Beihai area, that is, Lake Baikal, the territory of the original Xianbei people. He worked with Zhang Zha. Apparently he was Xu You.
Sun Quan was the one who wrote the novel, and maybe he didn't explain it clearly enough.
Liu Bei didn't mention it, but it was speculated in the previous chapter.
There should be nothing else that is relatively vague? (To be continued...)