@Wife of Sung Jin Woo from what I understood the East is unified and cannot be controlled by the Emperor. So Artezia proposed to "only" execute half of the prisoners (the Emperor wants to execute everyone, Duke Ebron wants to save everyone). This way Duke Ebron gets some of what he wanted and the Emperor gets what he truly wants, division in the eastern nobility. But from his poor health it seems like Artezia is actually just paving the way for when Duke Ebron will be the Emperor