Board Thread:Theories/@comment-17499145-20170509021147/@comment-29945764-20170626085131

I'm pretty sure Marley had the 9th titan because Marley still had 7 titans when Reiner was training to become a warrior as there were 7 candidates, but after the conclusion with the war with the south only 6 were going to be given titan powers. So I believe that at some point during the war with the South, Marley lost it somehow.