#1 Seth Rollins
Although it's still early days, it feels like all roads lead to Seth Rollins. His match with Brock Lesnar was a great way to finish SummerSlam, and The Beast managed to make Seth Rollins the champion he was supposed to be seen as after WrestleMania 35. While one threat has been neutralized, another lies on the horizon.
Though it's debatable that The Fiend would be after any title, it's a still a great possibility for deep dramatic storytelling. Imagine The Fiend going after Seth Rollins in a personal way and truly trying to break him and bring him down to his level. It's what The Joker tried to do to Batman and it's something Bray Wyatt could do to Rollins.
Assuming the title changed hands, Seth Rollins would have to regain his confidence to battle The Fiend wherever and whenever. After SummerSlam, WWE could go in so many directions with this.
With WWE Raw about to hit the airwaves, don't be surprised if "Firefly Fun House" is the highest-rated segment on the show. WWE has the audience's attention and they want to know who's next on Bray Wyatt's hit list.
Who do you think it is? I guess you'll have to tune in to find out!