Isn't this fight against lubu supposed to be with guanyu, zhangfei, and Liu bei.

I believe the first ep said that there is very little factual evidence in historical records for the events during the waring states period so most info and reenactments are speculation and theory by historians depicting their own views of how things played out and how it was living during that era

Yea, I guess... Sima yi wasn't even supposed to be born yet during this period of time. And diao chan was supposed to make out with lubu😆