I have already seen threads where people discussed Madara having the curse seal on his neck, if you look at page 14 you can see him rubbing that area. Now what I think is going to happen is that Orochimaru is going to try to take over his body in order to obtain the ultimate body that he truly desires. Considering that this is Orochimaru it doesn't seem to far fetched that he might have implanted his DNA in every curse seal he placed on a person. Think about it what did Orochimaru want. 1 The eyes of an Uchiha, 2. An immortal body, and 3 the ability to use all jutsu. Madara has the potential to learn every jutsu because of his sharingan and rinnegan so this makes sense in my personal opinion.:shrug: