I think he knows a lot. In the ED, the emperor is shown with VV. And it has been said that VV is actually the one CC is talking to most of the time, other than Lulu's mom of course. I also remember that the Emperor was not at all surprised at Euphie's sudden bloodthirst, he just went on saying that the fool[Lulu accdg to some sources] finally/actually did it..
(no subject)