HideoK on 21 July 2010
@Draven26
You can start doing c'ieth missions now, but you won't be able to 5-star majority of them until you are more powerful so I wouldn't try to do all of them now. You could do the first 7-9 missions which are easier D rank missions and their are also a few missions you'll come across in the story that you have to play. For the rest I waited until post game.
