Jeff Hardy and The Fiend
Jeff Hardy got his chance to shut down Sheamus in a Bar Fight match on Smackdown. Hardy, recovering addict in real life, used his personal experience and his way of life into the storyline. Sheamus played a big part of this role by believing that he will not stay clean. He kept pressuring him to drink only to get into a brawl.
Sheamus dominated the match but got to cocky as he went behind the bar to serve himself a drink. When he returned to Hardy, who was laid out, called the ref for the three count. It was then, Hardy turned into Brother Nero and started attacking Sheamus. Hardy climbs the ladder and lands his signature move for the win. Hardy's transformation can lead to another gimmick and a new feud for another superstar such as The Fiend.
At Extreme Rules, Bray Wyatt grabbed Braun Strowman from the edge and dragged him in the water (similar to what Jason would had done in the movie, "Friday the 13th"). It was thereafter, The Fiend came out of the red boiling water with Wyatt's evil laugh to end the program. On Smackdown, Wyatt came on the Fire Fly Fun House and this is what he had to say:
"Listen, you had your chance. Its his turn now. He has been unleashed."
Both Hardy and Wyatt have similarities and at a certain point, both will have to challenge one another or unite. Hardy did state on an episode on "After the Bell" podcast that he had an idea of taking part in a Firefly Funhouse Match with Bray Wyatt, similar to WrestleMania 36 when Wyatt defeated John Cena.
I predict Jeff Hardy and Bray Wyatt, Brother Nero vs. The Fiend at WrestleMania 37.