There's a paragraph near the end of John Kavanagh's memoir Win Or Learn that he probably meant as a throwaway line, but you can't help lingering on it just the same: "I've been Ireland's first MMA fighter, first Brazilian jiu-jitsu black belt and first coach of a UFC champion." He uses it to deflect and pivot and to set up another thought entirely, but it fairly jumps off the page and takes you by the eye.

This, you realise, is the guy. He’s to blame. For MMA. For UFC. For all the gore and all the bloodlust and all the frothing princesses who can’t let a pea of criticism lie idle online without seeking it out to take offence. For, yes, Conor McGregor.

This guy. Quiet, soft-spoken, 38 years old. Not posh by any stretch but comfortably middle class, Rathfarnham still in him long after he left it. Studious and data-driven, as befits someone who finished out an engineering degree to keep his parents happy while he set up his first gym in a damp kip down a Phibsboro backstreet. Good company, obviously intelligent, no Barbarian he.

For the next week or two, he’ll be talking into microphones, plugging his book and telling his story. But inevitably, inexorably, he’ll spend half his time defending his sport. This, he knows before he starts.

Strange or funny

"Yeah, I sort of have my stump speech down alright for defending it. Look, I'm about 15 years doing this at a decent level and I guess I still find it a bit strange or funny or maybe odd that I'm still only ever asked on to defend the sport. Nobody ever asks Katie Taylor why she likes punching girls in the head. Nobody ever says, 'Why do you like giving girls concussive blows to the head?' It's always just praise.

"I was thinking about this a little bit. In all the years I've been doing it – and I've achieved a bit, both myself and with my fighters and in setting up a successful business – I've never got a euro of help from the social welfare or a euro in grant money. I've never been a drain on the State. Everything here has been built from the ground up, starting with a loan that has long since been paid back.

“And yet all I’m ever asked is, ‘Why are you involved in this sport? How do you feel about your fighters elbowing people in the head?’ That’s always been the angle. It’s never been, ‘Well done, you guys have done great work here’. Whereas a couple of weeks ago we had Mick Conlon and Paddy Barnes in the gym to do some training with Conor and I’m just so envious of them. I look at them on Twitter or in the media and all you ever see is praise being heaped on them.

“It’s never, ‘Why do you like punching guys in the head?’ It’s never, ‘There’s an average of 11 or 12 pro boxing deaths each year – are you worried about what you’re getting into?’ It’s always positive. So I’m certainly envious of that.”

Envious but relaxed, on the whole. There was a time when he would call into radio shows to try and change people’s minds about MMA, but these days he mostly just tunes out the noise. Not because he is careless or reckless about the violence involved or blithely above the fray. The opposite, in fact.

Level of injuries

"The other thing I'd say is that statistically it's no more dangerous than a load of other sports I could sit here listing off. And if my sport was running away off into the distance when it came to the level of injuries sustained – which it isn't and there's data to show it isn't – then I'd be out of it without a second thought.

"I would leave it on the spot and I wouldn't have anything to do with it. I wouldn't be able for that role of knocking on doors every week to tell a mother that her son has got mangled in a fight that I put him into. I wouldn't have the stomach for it."

Kavanagh got into martial arts because he was sick of being scared. He was bullied as a youngster and whereas plenty of kids in that situation just remove themselves from the environment, Kavanagh faced into it full bore. How come?

“I think it was because of my dad. I was always in my dad’s shadow because he was so tough. There were always stories about my dad taking on 10 guys or whatever – I actually saw him do that. Whereas I was afraid of my own shadow. I just remember being afraid all the time. I had a totally nervous disposition. If I heard a car horn going, I would jump a mile in the air and I would spend what seemed like hours afterwards trying to bring myself down.

“The whole time, I felt weak because I couldn’t do what he could do. I would just freeze and let someone hit me and hope they moved on. Whereas I did once see my dad take on 10 people. He got the hell beat out of him, but I did think that was amazing that he would stand up to people like that.”

He did karate for a while but eventually found it of little use for his purposes. The final straw came when he got beaten up on a night out in Rathmines in front of his then-girlfriend. The kicking, he could take. But the humiliation flicked a switch.

Humiliated

"I had won some national titles in karate by that stage but I just didn't feel I could transfer what I knew to a self-defence situation. I was great in a quiet dojo with friends. But when I was faced with an aggressive person, I just shrunk. That was what happened in Rathmines that time and I was humiliated as a result.

"I could have gone one of two ways. I could have decided never to have anything to do with martial arts again and associated it with that incident for ever more.

“But I went the complete other way. I got really serious about it and eventually found MMA. Even if that situation never came up again, I just wanted to be comfortable in my own skin. I just wanted to be okay walking around.”

The rest is a history that looks to have plenty of writing left in it yet. Fighting gave way to coaching after a few years – Kavanagh says that in another life, he’d have been a maths teacher. The sport took off, the UFC happened, McGregor happened. Kavanagh’s Straight Blast Gym bounced around from home to home before settling on the Naas Road. Life was peachy.

Until it wasn’t. In April this year, Kavanagh was in Charlie Ward’s corner for the bout with Joao Carvalho after which the Portuguese fighter collapsed and died. The aftermath was loud and unpretty, but it passed inside a couple of days for most people. For Kavanagh, it hasn’t passed yet and isn’t likely to for a while.

Devastating

"It wasn't something I had prepared for. I never had anything as bad happen. All my life, the sport was only a positive. And then suddenly, the worst thing happens. A death in the cage. I don't know if you could call it a wake-up call but it was devastating. It was really devastating. It made me question why I was doing this. Should I walk away from it? I got into it to help people.

"I had never thought about it. I never thought that one day I might have to go to somebody's parents and say, 'Sorry, your son died under my guidance'. I had never entertained that. It was just something I enjoyed and it was fun and it was nothing but a positive experience for me. And then I had this. And of course I had to think of it the other way around – what if I had to go to Charlie's wife?

“But the only thing that got me through it and got me out of it was the fact that this is just an inevitability in all high-level contact sports. After a while, rational logic kicked in and I started doing the numbers in my head. The tens of thousands of people who do this worldwide, maybe hundreds of thousands. The people who do it to lose weight, to gain confidence, to stay out of trouble, whatever their reason.

“If you do the numbers on car journeys, if you run enough of them, there’s going to be a crash. It’s a statistical inevitability. It’s the same if you run enough boxing matches or rugby matches or whatever. If you run enough MMA fights, this is going to happen. You either have to accept that or you have to lock yourself in a room and decide not to be involved in those types of sports.”

Not much chance of that. He wouldn’t know how.