I think the reason.he wears a mask is to distance himself from rest of ninja world
thats true, but I cant help think that theres something really dodgy to him, with how he always hides behind the mask (although he did remove it for sasuke). Just assumed the coffin could have been his "body" but you make a good point. Wonder how long it will be till Kabuto decides to make his move and reveal what it was.
It can't be madara.in coffin unless this isnt madara cause even if kabuto found his body that isnt how edo works.