#1 Randy Orton
As mentioned earlier, Bray Wyatt entered an interesting period in his career after the 2016 WWE Draft, which ultimately led to the death of the Wyatt Family. That happened courtesy of Randy Orton. This was the single most damaging thing that happened to Wyatt's character, both personally and professionally. The Fiend might not have even been born if not for this grave injustice.
After realizing mid-feud that he couldn't beat Bray Wyatt, Orton decided to join him and form the 'New' Wyatt Family, along with Luke Harper. The three terrorized SmackDown, with the Viper looking the most interesting he had been in years. He won the 2017 Royal Rumble, while Wyatt won the WWE Championship.
A former WWE writer just went after JBL for his comments HERE
The two were on a collision course at WrestleMania 33 and after causing Harper to leave the group, Orton turned on his "master". He burned down the Wyatt Family compound and won the WWE Title from Wyatt at 'Mania. This caused the 'Eater of Worlds' to suffer irreparable damage, until The Fiend came along.
The main premise of The Fiend is going after everybody who wronged Bray Wyatt. And nobody has wronged him more than Randy Orton. And with Superstars moving brands lately, the Viper could shift to SmackDown after his program with Edge has concluded.
This is the most storied match The Fiend could have at the moment, with vengeance on his mind. It may even form the second-ever Firefly Fun House Match, with Orton's career being deconstructed by Wyatt in the form of mind games. A reversal of their storyline between 2016 and 2017.
The evil act of setting Bray Wyatt's house on fire warrants such extreme measures for sure. And this match will happen sooner or later, as The Fiend never forgets.