 Isayama estimated his basic monthly timeline as one week to storyboard and three weeks to actually draw the chapter . The story is planned out in advance , even marking down in which collected volumes a specific " truth " will be revealed . In September 2013 , he stated that he is aiming to end the series in 20 collected volumes . Originally , Isayama planned to give the series a tragic conclusion similar to that of the film adaptation of Stephen King 's The Mist , where every character dies . However , positive response to the manga and anime has caused the author to contemplate changing the ending due to the impact it could have on fans . 
