#6 Roman Reigns has never held a World title for more than 100 days
Roman Reigns has held a World title four times so far. He's won the WWE Championship thrice and the Universal title one. Both the current holders of these belts – Drew McIntyre and Braun Strowman – have been World Champions for over 100 days now, something that The Big Dog is yet to do in a single stretch.
Roman Reigns' first World title victory came back in 2015 when he won the tournament to crown the then-vacant WWE World Heavyweight Championship by beating Dean Ambrose in the final at Survivor Series. Unfortunately for The Big Dog, Sheamus cashed in his Money in the Bank briefcase moments later and ended his reign immediately.
Reigns would claim the title back on the December 14 episode of RAW that year only for him to defend it during the 2016 Men's Royal Rumble Match. Triple H entered the contest at the #30 spot and eliminated Roman Reigns followed by Dean Ambrose to win the Championship and end The Big Dog's run at 41 days.
Reigns' final run as WWE Champion lasted for 77 days with him winning the title at WrestleMania 32 and dropping it to Seth Rollins at Money in the Bank. He beat Brock Lesnar at SummerSlam two years later to win the Universal Championship but had to vacate it 63 days later as The Big Dog got diagnosed with leukemia.