Board Thread:Fanon Canon 2/@comment-2185383-20140924182221/@comment-24384232-20140927191032

Actually Hiruzen did know about the massacre, though whether it was before or after I'm not sure. But he was aware of the Uchiha's plot to overthrow him. As the Hokage he has a responsibility to save his village, even if it meant the destruction of an entire clan. Were it not for Itachi begging the Sandaime to spare his brother and protect him, Hiruzen would have paid no heed as to whether Sasuke lived or died. Kage can be utterly ruthless.