It is but a shell , nice place for a demon to take over , in other words absolute control if it can manipulate the brain to its own ends ! It would have to be a wandering demon who comes across a cloned being by accident , I doubt clones would initiate a ritual but of course Humans could summon a demon and invite them to occupy said clone , things start to get a little bit interesting at this point. The battle between the soul / demon would not exist therefore demonic power would be unobstructed and it would be able to lash out at will .