I just downloaded the mod and jumped into my first campaign as the Sun dynasty and saw Taishi Ci working for Liu Yao. I thought defeating him in battle with Sun Ce would be enough to get him to join me but he ended up dying in the first battle . He then retreated after my second attempt.
I can't seem to find any list of triggers on the forums but I did see that there was a new model for Taishi Ci after the trigger so at least it is possible. Any help would be awesome.