In ep 26, notice Wang Qinian left before Xi Bi'an came. FX probably send him off to get help. My guess is he went to look for Wu Zhu who is nearby fighting with Ku He. My guess for the opening act of season 2 is Wu Zhu slaughtering the lot of them.
I have already finished the drama but I am still confused about the marriage between Si Lili and the emperor of…
i don't think they confirmed there is a marriage. they just guessed it would happen because the northern qi emperor called for si lili to be freed. but there may be another reason the emperor called for si lili to be freed