Theon Greyjoy — Cameron Monaghan
At this point, it is safe to say that Cameron Monaghan will be a Hollywood fixture for many years to come. After making a name for himself through Shameless and Gotham, Monaghan is primed to make another leap with his acting. Monaghan has shown a knack for playing both a lighthearted and serious role, and would have no problem capturing the essence of Theon Greyjoy. The California native is a very likable actor, which would make his despicable actions as Theon all the more powerful.