Secret code.... so, is Sima Yi's words when speaking to Xun Yu supposed to be a message from The Eight/Zhao Sheng? Or is it something he planted somehow? Hmm, I don't know how the latter can work exactly, but I have heard that the reason Cheng Pu manage to not get hypnotized back when Sun Ce is alive is because he's just too smart, so I won't put it pass this series.