#1 Roman Reigns to challenge The Fiend's Universal Championship after SummerSlam
There's a possibility that WWE could insert Roman Reigns in a feud with the new WWE Universal Champion, The Fiend, immediately after SummerSlam. Reigns, after attacking The Fiend with punches, then proceeded to attack Strowman, before returning to the ring to land a spear on The Fiend.
He then told The Fiend that the Universal Championship "has always been mine" and that The Fiend is "just a freak in a mask".
The story for a feud between The Fiend and Roman Reigns is easy to set. Reigns was the one who was originally supposed to face Goldberg for the Universal Championship at WrestleMania 36, and feud with The Fiend following that. Reports had suggested that The Fiend lost his title to Goldberg so that Reigns could win the title from the WCW icon at WrestleMania 36. But, Reigns' absence from The Show of Shows meant that Strowman won the title, before losing it at SummerSlam.
Reigns' sole reign as Universal Champion ended because he had to relinquish the title due to being diagnosed with Leukemia. This is a title that Reigns never lost and he deserves a shot at the title.
Next week's Payback pay-per-view may be too soon for a Reigns-Fiend match, but they could begin their build for the match on the SmackDown after SummerSlam, and perhaps face off at Survivor Series.