#1 Finn Balor

Finn Balor has been a changed man ever since his match with The Fiend at SummerSlam and while his momentum isn't moving as strongly as it was upon his heel turn in NXT, he could right the ship by winning this year's Royal Rumble. Heck, it could even be what sets him back on a collision course with The Fiend to get revenge and finally reclaim his Universal Championship after over 3 years.
Not only would this allow WWE to go full circle with the beginning of Bray Wyatt's "The Fiend" gimmick, it is also a chance for WWE to do a supernatural style match. In fact, between Balor's Demon King person and Wyatt's Fiend character, all the building blocks are there for the company to have a match of supernatural proportions.
WWE already proved they can handle a supernatural gimmick with The Fiend over the past couple of months, which should hopefully be a sign that they will do more of that in the future. Balor being The Fiend's first official opponent would only be icing on the cake and allow the company to build an even bigger story around it.
Becky Lynch has been challenged HERE.