A long time ago, to Shan You, Si Nan was the combination of all good things;
Many years later, to Shan You, Si Nan was a big bad wolf in sheep's clothing.
A long time ago, to Si Nan, Shan You was a gentle moonlight that illuminated his world;
A long time later, for Si Nan, Shan You was deeply embedded in the bone marrow and blood, and could no longer be removed.
It is purely the YY work of the author's wild imagination.