Naoya Inoue’s development into perhaps the best fighter on the planet today has been a long series of transformations. 

As a child, Inoue was boxing recreationally alongside his brothers, his father Shingo having moved on from his outstanding amateur career to focus on his painting business. It didn’t take long for Shingo to discover that the child he called “a little angel” was a prodigious boxing talent however, and he decided to come back to the sport full-time to foster his son’s skills. After coming up short in the All Japan amateur tournament while he was in high school, Naoya said he “became a demon.”

It would be the last time he would lose a boxing match. Inoue turned pro, and initially asked ring announcers not to call him The Monster, but Chairman Hideyuki Ohashi insisted he keep it. He lived up to the reluctant nickname quickly, winning the WBC light flyweight title in just his sixth professional fight, placing him in rare company amongst fighters who won legitimate world titles that quickly. Inoue was just 21, and with his shiny black hair and 108-pound frame, looked innocent next to the battle-hardened Hernandez, who by that point had been a professional for eight years. By the end of six rounds however, Hernandez had been rescued from the fight by referee Michael Griffin. Both of Inoue’s shoulders were splattered in Hernandez’s blood as he collapsed in the center of the ring, overcome with emotion after his momentous win. The demon had returned to angel form. 

Eight years later, Inoue’s mantle is filled with hardware. World titles in three divisions, Prospect of the Year, Fighter of the Year, Fight of the Year and at a Pound For Pound No. 1 designation from various outlets. On Tuesday in Tokyo, he’ll have an opportunity to make not just Japanese boxing history, but Asian boxing history by becoming the first undisputed champion in the four-belt era from his country and continent as he takes on Paul Butler with all four divisional belts on the line. 

Now 29, one gets the sense that Inoue is feeling a hint of nostalgia, perhaps appreciating his accomplishments both past and present a little bit more. When Inoue appeared for the final press conference in Tokyo last week, the frosted tips of dyed blonde hair we’d been accustomed to seeing him with here gone, which Japanese reporters immediately took notice of. 

"The last time my hair was black, I was 21," said Inoue, harkening back to the time of his first world title win. "I think I'll go back to the beginning."

Inoue has reached a point in his career in which athletes and those who cover them start to reminisce and contextualize their accomplishments. The bulk of Inoue’s career has passed, and the vast majority of his major accomplishments are already commemorated somewhere in his home. That isn’t to say that Inoue doesn’t have much left in the tank—his most recent destruction of Nonito Donaire in their rematch proved he most certainly does—but the reality is that Inoue probably doesn’t have another eight years of active competition in him, and certainly doesn’t have three more weight classes to climb to. Inoue told Daisuke Sugiura earlier this year that he thinks featherweight is his ultimate weight limit as a fighter, and that he has “no intention of fighting in weight classes (he doesn’t) belong in.” In terms of the hourglass, Inoue has said several times over the years that he doesn’t want to fight past the age of 35, but has more recently backed off of that hard stance. 

"When I see the four belts lined up on the stage, my motivation increases, and I'm full of feelings that the final chapter in the bantamweight class is finally here,” said Inoue at the final press conference. 

The bout against Butler is, at least in the eyes of oddsmakers, one of, if not the most lopsided undisputed title fight in boxing history. This says more about Inoue’s ability than any lack of it that Butler may have. Butler is a consensus Top 10 divisional fighter and a two-time world champion, yet the best bookies can see him as at this point is a 40-1 underdog, and some lines have been even wider. 

The threat of a blowout sounds even more imminent when hearing Inoue speak. Nearly every fighter defines their latest training camp as their best ever, but Inoue was even more specific, stating that he is “1.5 times stronger” than he was against Donaire last time out, both physically and mentally. It’s a frightening proposition, considering that at his weakest point and under the most duress he’s ever felt in a boxing ring in his first bout against Donaire, with a broken orbital bone obscuring his vision, he still outlanded Donaire 82-34 in the final three rounds according to CompuBox’s Dan Canobbio. 

Despite all of this, Butler proclaimed that he feels Inoue has some weaknesses defensively, which prompted the previously smiling and laughing Monster to get a little more boastful in response. 

"I'm confident that if I really focus on defense, I won't get (hit with) a single shot. Actually, I want to show that defense is my best (characteristic),” said Inoue. 

With maybe the best offensive arsenal this generation of boxing has seen, Inoue has never really needed to put his defensive acumen to use. The moments when he does are more likely to happen against the likes of Stephen Fulton a division north, a fight that nearly all fans are salivating over.

For now, he hopes to bag another achievement that will seem more difficult on paper than it may be in practice for him. It’s the burden of Inoue’s gifts that a fighter of Butler caliber is seen by observers as an utter waste of time for him as an opponent. But it’s in these moments we can truly appreciate the elite, the breadth of the gap in talent between the division’s best and its sixth best, and how unthinkably wide it can somehow be.  

Corey Erdman is a boxing writer and commentator based in Toronto, ON, Canada. Follow him on Twitter @corey_erdman