Kind of obvious it was the Empress, and probably the Emperor too, even though I hoped he wouldn't be involved. Well maybe it's for the best. I won't feel slightly bad to see him dead.
As for their intentions, the Empress probably wants her child as heir to the throne (if she has one), and the Emperor..... He's either damn stupid or damn petty. Anyway, now that everything has been set, let's see where the plot goes.