Standing over two meters tall, weighing in at around 300 pounds, the Frenchman possesses an aura of invincibility few can match in the history of sport.
The numbers speak for themselves. Riner has reigned supreme for approaching a decade, winning 134 consecutive matches on his way to securing a record nine world titles.
Just as a judo match always starts with a bow, a confrontation with Riner inevitably ends with defeat.
Surely then only a fool would bet against the 28-year-old adding another gold medal to his collection at November's Judo Open Weight World Championships?
"Riner is a great champion. A legend. But I think in an open weight tournament he's in more danger," former world champion Neil Adams
tells CNN Sport. "There are quite a few light heavyweights that are going to be pushing Riner and running him ragged.
"If he has to step into a place he's never been before, then you could see a couple of surprises. The David vs Goliath situation? It's very exciting."
Returning to the judo calendar for the first time since 2011, the prestigious Open Weight World Championships bring together male and female fighters of all shapes and sizes.
With that in mind, Greek judoka Ilias Illiadis has come out of retirement for a shot at gold, a full thirteen years after he became the sport's youngest ever Olympic champion in the Athens 2004 middleweight (-81kg) division.
Whether any of the lighter contestants can replicate the feats of 5ft 7in, 80kg judoka Isao Okano -- winner of the open class at the All-Japan Championships 1967 and 1969 -- remains to be seen.
But Adams himself has experience of fighting -- and beating -- far heavier men.
"I used to fight open weight tournaments really well," he says. "You don't just stand there. If you stand toe-to-toe with Mike Tyson, he's going to hit you. You're going to go down.
"You run, dance and wait for a mistake. You try and take them to a place they've never been in terms of condition.
"If you look at the pace of the heavyweight division, it's a lot slower. It doesn't mean that the techniques they execute are slow, it's just the pace of the match.
"You have to take them out of their comfort zone. Obviously what everyone wants to see is people going out there to give Riner a good fight."
A record €500,000 prize pot is up for grabs this weekend in Marrakech, Morocco, with champions taking home €100,000 ($116,340). CNN Sport profiles the ones to watch.
Ones to watch
Guram Tushishvili (Georgia)
Few have come closer to toppling judo's king in the past seven years than explosive youngster Guram Tushishvili.
One of four Georgians fighting at the Open Weight World Championships, the 22-year-old forced Riner to golden score during this year's World Championships in Budapest,
despite being the lightest judoka in the division (111kg).
Neil's prediction: "There are quite a few lighter heavyweights in there that are going to be pushing Riner and running him ragged. Tushishvili is going to keep moving and, if Riner faces two or three more mobile competitors on the trot, it could be very difficult for him to sustain the pace."
Naidan Tuvshinbayar (Mongolia)
Mongolia has punched above its weight on the tatami ever since Naidan Tuvshinbayar became the east Asian nation's first ever Olympic gold medalist in 2008, crowning four world champions in the years since.
He may stand at just 5ft 10in, but Tuvshinbayar himself will be hoping to do the same at the Open Championships. The 33-year-old veteran beat far larger men to win bronze at the 2017 World Championships
Neil's prediction: "With three male entrants, there might be a surprise from the Mongolian contingent."
Ilias Iliadis (Greece)
Thirteen years after becoming the youngest Olympic judo champion in history at the age of just 17, Iliadis has returned to the tatami.
It will take the performance of a lifetime -- he has traditionally found success in the lighter -81kg and -90kg divisions -- but don't write off the three-time world champion just yet.
Neil's prediction: "Iliadis is very very special. He is a warrior and he'll come out fighting with all guns blazing."
Cyrille Maret (France)
Bronze medalist in the half heavyweight (-100kg) division at Rio 2016, Maret has since stepped up to the highest weight category.
The 30-year-old capitalized on the absence of his compatriot Riner to win the heavyweight division (100kg+) at October's Abu Dhabi Grand Slam, and heads to Marrakech in great form.
Neil's prediction: "I think Maret is going to be the surprise package. Watch out for him! He probably knows Riner better than anybody and he fights heavyweights very, very well. If anyone can beat Teddy, for me it's him. "
Sarah Asahina (Japan)
It is testament to Asahina's ambition that the 21-year-old came away from her first ever senior World Championships disappointed with a silver medal.
"I didn't expect to reach the final in Budapest, but I hope and I will get a gold medal at the Tokyo Olympics in 2020," the Japanese heavyweight (78kg+) told CNN Sport.
Neil's prediction: "Asahina for me is the favorite. She will come to it with something to prove after the World Championships. I thought she was unlucky in the final not to win it. Of the up-and-coming generation, she's one the best for technique in the heavyweight division at the moment.
Idalys Ortiz (Cuba)
With Olympic medals of ever color to her name, Ortiz brings over a decade of international experience to the tatami.
The Cuban heavyweight, 28, hasn't fought since the Rio 2016 Olympics.
Neil's prediction: "Ortiz of course will be somebody capable of causing problems because of her experience, but I'm not sure she's one of the favorites this time. For me I think some of the dangers will come from the light heavyweights that have stepped up."