It’s just a theory!
But don’t you think that these two characters are very similar? Like brothers.
Why Situ Li is always get mad at Xi and wants to kill him? To this must be a serious reason.
Why Xi doesn’t do anything? Why don’t he fight seriously with Li?
Also, did you noticed when he went to the grave, he took with him a music player. He always listens to music in it (Zhang Xuan’s music?).
Is it possible that Zhang Xuan (Situ Li brother) died due Xi faults? Therefore, Li is always angry, and Xi does nothing. He feels guilty.
It’s just a theory, but oh my brain!