Most wrestlers need months to get a reaction from the crowd. Mason Rook needed one moonsault. It happened on a Tuesday night in April 2026. A massive, unfamiliar face showed up during an NXT segment, climbed to the top rope, and dropped a moonsault on reigning NXT Champion Tony D’Angelo. Nobody in the arena knew his name yet. By the next morning, wrestling fans everywhere were searching for him.
That single moment is why casual fans know Mason Rook. But the character has almost a decade of work behind it. Before WWE ever called, William Walker had already built a name for himself on two continents. Here are 10 Things You Didn’t Know About Mason Rook.
1. He’s British, and It Shows in How He Wrestles
Mason Rook’s real name is William Walker. He was born on October 28, 1996, in Worksop, a market town in Nottinghamshire, England, according to his official wrestling profile.
Watch him work and you can tell he came up on the UK independent circuit — hard chops that land with real force, physical exchanges, a style built around making contact feel real rather than choreographed.
2. His Training Started at a Small Gym in Lincolnshire
Before the WWE Performance Center, Walker trained at Fight Factory Wrestling (FFW) in Lincoln, under coach Hayden “Dutch” Loeve. FFW isn’t a household name in America, but it has a solid reputation on the UK indie circuit and has produced several wrestlers who went on to bigger promotions. Walker spent years working through FFW’s academy system before ever stepping into a WWE ring — a big part of why his transition looked so smooth.
3. He Wrestled for Years as Will Kroos
Walker’s ring name on the independent scene was Will Kroos. He beat Shogun J in his professional wrestling debut on May 26, 2017, at Hope Wrestling’s Evolution 47. From there he worked his way through smaller shows and modest crowds, but the hard-hitting style stuck with him the whole way — and it’s still the trait that defines him today as Mason Rook.
4. He Won Titles Before WWE Ever Noticed Him
Kroos challenged for the FFW Academy Championship against Magic Myers back in January 2017, early proof that promoters already rated him. His biggest indie accomplishment came later: he beat Gene Munny to win the PROGRESS Atlas Championship at Chapter 184 in September 2025, then successfully defended it against Charles Crowley the following month before eventually dropping it to Saxon Huxley during a run in Japan. The Atlas title exists specifically to showcase big, powerhouse-style wrestlers — and Kroos held it as a legitimate champion, not a novelty.
5. He Wrestled in Japan for Pro Wrestling NOAH
Kroos also worked matches for Pro Wrestling NOAH, one of Japan’s most respected promotions, known for hard-hitting, physical wrestling where every near-fall matters. That’s a very different test from the UK indie scene, and it shows in how comfortable Rook looks against bigger, more experienced opponents in WWE now.
6. His Nickname Predates His WWE Contract
The chant “He’s big, he’s bad, he’ll bodyslam your dad!” wasn’t written by WWE’s creative team. It started on the indie scene and has been widely credited to Maffew, creator of the wrestling comedy series Botchamania, though the exact origin has never been pinned down with full certainty. Fans were already chanting it for Will Kroos years before he signed with WWE. Most call-ups have to build a connection with a new audience from zero. Rook walked in with a chant fans already knew by heart.
7. John Cena Publicly Backed Him Before His Debut
John Cena noticed Kroos on the independent circuit and publicly praised him as a talent worth watching, well before Rook ever wrestled a WWE match. A cosign from a 17-time World Champion is rare for an indie wrestler with no mainstream exposure — and it raised expectations for Rook before he’d thrown a single punch on WWE TV.
8. His Debut Was an Attack, Not a Match
Rook’s first WWE appearance wasn’t a wrestling match — it was an attack. On the April 28 episode of NXT, he blindsided NXT Champion Tony D’Angelo before introducing himself under the Mason Rook name. His actual in-ring debut came weeks later, on May 19, teaming with Kam Hendrix to beat D’Angelo and Myles Borne. Both moments told the same story: WWE wasn’t positioning him as another rookie finding his footing — he arrived as a threat.
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9. His Contract Signing Turned Into a Brawl
WWE could have played his contract signing straight. Instead, Tony D’Angelo interrupted from the stage to warn Rook off, Kam Hendrix attacked D’Angelo from behind, and the whole thing turned into a brawl. In the middle of it, Rook climbed the ropes and moonsaulted the pile — D’Angelo, Hendrix, and ringside security included. Then he calmly walked back and signed the contract like nothing had happened. That single beat told fans exactly who this character is: unbothered by chaos.
10. He’s Bigger Than He Looks in Motion
WWE lists Rook at 6-foot-4 and 408 pounds on his official WWE Superstar profile — numbers that suggest a pure powerhouse. But he regularly pulls off moonsaults and springboard moves you’d expect from someone half his size. That size-to-agility combination is exactly why NXT fans didn’t need months to get invested — the first time he flew off the top rope, the point was already made.
Bonus: John Cena Made His Support Official On Record
Cena’s early praise for Rook wasn’t a one-time thing. In a recent interview With CBS Sports discussing WWE’s next generation of stars, Cena brought up Rook unprompted and made his support explicit — he said he chants along with the “He’s big, he’s bad, he’ll bodyslam your dad” chant himself, and told anyone unfamiliar with Rook to go check him out, closing with a simple line: he’s a fan.
Coming from a 17-time World Champion, that’s not casual praise — it’s a public co-sign that keeps Rook’s name in the conversation every time Cena talks about WWE’s future.
Where Mason Rook Stands Now
Rook’s momentum hasn’t slowed since his debut. He lost an early shot at Tony D’Angelo’s NXT Championship after Naraku capitalized on interference from Kam Hendrix in June 2026. But by September, he was firmly back in the title picture: on the September 8 episode of NXT, Rook teamed with Tony D’Angelo and Saquon Shugars to win a six-man tag match, earning all three men a place in a Triple Threat match to determine the next No. 1 contender for the NXT Championship — now held by Grayson Waller after his win over D’Angelo at Heatwave. Rook’s push toward the title picture is very much still in motion.
FAQs
Who is Mason Rook in real life?
Mason Rook’s real name is William Walker. He’s an English professional wrestler born on October 28, 1996, in Worksop, Nottinghamshire.
What was Mason Rook’s wrestling name before WWE?
He wrestled as Will Kroos on the British independent scene and in Japan, before WWE gave him the ring name Mason Rook in 2026.
How tall and heavy is Mason Rook?
WWE lists him at 6-foot-4 and 408 pounds on his official Superstar profile.
Where did Mason Rook train?
He trained at Fight Factory Wrestling (FFW) in Lincoln, England, under coach Hayden “Dutch” Loeve, before signing with WWE.
What titles did Mason Rook win before joining WWE?
As Will Kroos, he held the PROGRESS Atlas Championship, beating Gene Munny for the title in September 2025 and successfully defending it against Charles Crowley before losing it in Japan.
Did John Cena really endorse Mason Rook?
Yes. John Cena publicly praised Kroos on the independent scene before he ever signed with WWE, and later reacted to his NXT debut on social media.
Where does Mason Rook’s “He’s big, he’s bad” chant come from?
It started on the UK independent scene and is widely credited to Maffew, creator of the wrestling comedy series Botchamania — years before Rook ever signed with WWE.
Is Mason Rook currently chasing the NXT Championship?
Yes. As of September 2026, he’s active in the title picture on NXT, with Grayson Waller currently holding the championship.
About Gaurav Sharma
I am the founder, lead writer, and editor behind Wrestling Nightmare. I have been analyzing and following professional wrestling for years, with a deep focus on WWE, AEW, and TNA—spanning the Attitude Era, the Ruthless Aggression transition, and modern long-term booking eras like The Bloodline. My work centers on breaking down in-ring storytelling, creative booking decisions, and the business landscape of combat sports entertainment. When I am not breaking down pay-per-view match structures, I am tracking roster movements, injury reports, and backstage creative pivots to deliver grounded, hype-free pro wrestling analysis.
contact@wrestlingnightmare.com
