Israel Adesanya reflects on the deep-rooted respect, discipline and family bond that makes his training home at City Kickboxing the ideal fit ahead of UFC 243. (1:48)

Under slate gray skies, a train rumbles through a light industrial estate on the Auckland city fringe, bound for the commuter belt suburbs west, before it swings north to Waitakere and towns beyond.

The city workers heading home will barely have glanced away from their phones and out of the window into the late winter dusk. If they had, they may have seen a nondescript warehouse that just happens to be the home to one of the Southern Hemisphere's greatest collection of combat athletes. Working in here are Israel Adesnaya, Alexander Volkanovski, Dan Hooker and Kai Kara-France. Contenders ready to be turned into champions. Welcome to City Kickboxing.

It's here in the Mount Eden suburb that office workers come to shed pounds, or hone up on some Muay Thai skills, and where wannabe combat athletes come to learn the ropes. It's also here where champions emerge, developing their craft and forming their style. Where talented MMA fighters are moulded into greatness, and are readied for the big stage, all under the watchful eye of head coach Eugene Bareman.

"At my gym we definitely play the long game. The skills we teach from an early stage take a decent amount of learning and repetition before you can become proficient at them," Bareman tells ESPN.

Bareman, an MMA fighter himself, has taken his gym and its fighters into rarefied air, with a succession of eye-catching performances putting City Kickboxing on the map. It's a no-frills space, though new, as demand for time in the gym necessitated moving to a bigger facility in recent months. An octagon, wrestling mats, heavy bags, spin bikes for recovery, all positioned around the space designed for work, effort and dedication. If you want to IG your workout gear, this ain't the place.

Israel Adesanya is flanked by City Kickboxing coach Eugene Bareman (L) and fellow fighter Brad Riddell (R). Mike Roach/Zuffa LLC via Getty Images

The word on the gym is out, and people are flocking in. The public and also the cream of local fighters all wanting to be better. At the head of it all is the modest, unassuming Kiwi Bareman. He rarely enjoys the spotlight, but is unequivocal over what it takes to succeed in MMA.

"A lot of trainers and gyms take a very shortsighted approach and teach a very raw, overly aggressive set of fundamentals heavily reliant on athleticism. They don't progressively add skills periodically as the athlete advances their career. This approach is fine at a low level and will definitely win you your first few fights in the short term. The problem is as the athlete meets better opponents with more refined skillsets he will undoubtedly begin to struggle at the higher levels of competition."

For Kai Kara-France, the No. 7 ranked flyweight in the world, it's the perfect environment to become a champion.

"It's one of these places; the atmosphere that Eugene has created that we can thrive in on a weekly basis. We've got so many guys fighting, not just in the UFC but all over the world in different combat sports in boxing and kick-boxing, that just adds motivation that when you go to your fight, you've still got 10-20 guys training for their fight," France tells ESPN.

"That just keeps the circle revolving, and once you come back from your fight you help out the next person who's got their fight coming up."

Kai Kara-France celebrates his win over Raulian Paiva at UFC 234 in Melbourne, February 10, 2019 Jeff Bottari/Zuffa LLC/Zuffa LLC via Getty Images

Even without Kara-France, who won his recent bout in Shenzhen, and new UFC 245 headliner Alex Volkanovski, Bareman will be taking a large group of talented tyro's across the Tasman for UFC 243 in Melbourne. Dan Hooker, Luke Jurmeau and headliner Israel Adesanya will all fight under the City Kick Boxing flag, along with the latest prospect to graduate through the gym, welterweight Brad Riddell, who'll make his UFC debut at Marvel Stadium.

"We're led really well. A lot of people say, 'What happens at the top falls to the bottom,' and what your gym sort of preaches and practises and the way its ethics are ... it runs through all of us. Obviously they train us really well, but they've built this culture here that's unbreakable. It's the culture, it's a process that's built on years and years of experience," Riddell tells ESPN.

"We've got Sydneysiders, we got guys from Texas and Japan. ... It's mental and awesome, because you get looks at fighters with all these different skills.

"The culture is one that d---heads aren't going to last long here."

It's an environment that has allowed the unique talents of Adesanya to flourish. "It's the culture of the gym," the interim middleweight champion tells ESPN on a visit to his Auckland home.

Despite hailing from Sydney, Alexander Volkanovski trains at City Kickboxing in Auckland. Josh Hedges/Zuffa LLC/Zuffa LLC via Getty Images

"We're a family and it's a fun-loving place to train, but if you mess up you have to know your role as the student, as the pupil (and accept that). I think that's been lost in other places a little bit throughout the years with some of the bulls--- people do in martial arts.

"I feel like it's about what's best for you as a person, and you as an athlete. I feel that the vibe over there, and the trainers that work on me at City, is the best for me."

For Bareman it goes beyond just the needs of the individual athlete.

"It's a team, a band of brothers and sisters, a tight-knit group of people who have the same interest, to become the best martial artist they can be. Permeating through the group is the idea that they need each other to succeed and any sort of help we give each other has to be reciprocated," he says.

It's an environment that breeds success and collaboration. A place where senior fighters can inspire and mentor others, through actions, deeds and example. Riddell has reaped the rewards of this approach.

"A lot of us have fought each other. If you wanted to fight, you had to fight your friends. I've had to share the cage with plenty of friends, but instead of trying to compete with each other we try to level-up one another."

"The knowledge (in Adesanya and Hooker) is unreal. The experience they have in MMA is amazing. I've spent a lot of time travelling around the world with Israel fighting kickboxers and stuff like that, so I watched him develop and watched this freak emerge -- this person who is an outlier from the normal realms of people. It's crazy to see," Riddell says.

"I'm always stealing off them and trying to do what he does. He's just so athletic, and he's so smart in [the cage]."

Brad Riddell has made his first UFC card, and trains at City Kickboxing in Auckland. Chris Hyde/Getty Images

New Zealand is writing a rich chapter in UFC history with this current generation of MMA athletes. It's a chapter that has much to do with maximizing the opportunity and wringing out every drop of talent available. For Riddell, the reason behind the success is also tribal.

"We're just two islands full of warriors. Everything New Zealand does, sporting wise, we just go full throttle," he tells ESPN.

"We have, I guess you could call it, small man syndrome, like little people who want to prove they're bigger. Our entire country wants to prove that just because we have 4 million, that we can compete and it doesn't matter how many people we're up against. That's a big part of it and we're a proud nation."

It's a view shared by Kara-France.

"Last year in the UFC our gym went 12-1, which is pretty unheard of from such a small country and how the UFC is so global. The majority of MMA is in America and with the massive gyms over there, (for City) to be ranked in the top five in the world, that's full credit to our coaches and the fight team. We already knew that this was going to happen a few years ago, but it's nice to see the recognition and everyone else taking notice to see that we're not just here to make up the numbers."

For Bareman, Riddell's emergence is another step on the journey he and his gym are taking.

"I take great pride in my team's success and I am acutely aware of all the people that contribute to the team's success. Without their contributions, regardless of how small or how big, it wouldn't happen. Each element is an important part of the success the team experiences," Bareman says.

"The other legacy that is just as important, is that I hope my gym continues to have a positive influence on people's lives in some way, shape or form. Whether it be someone who comes in simply to get fit or lose weight, or someone who wants to be a UFC champion, I want the gym to be able to affect both those people's lives equally."