Brandon Moreno enters UFC 323 looking to reclaim momentum in a division he once ruled. Long before he became a two-time flyweight champion, fans knew him for something far more unexpected, one of the most unusual nicknames in the UFC, “The Assassin Baby.” It sounds playful. It sounds confusing. And yet, it has followed him from his early regional fights all the way to world title bouts.

So how did a fighter with world-class grit end up with a moniker that sounds more like a cartoon character than a cage warrior? Let’s break down the story behind one of MMA’s most iconic nicknames.

How Brandon Moreno got the nickname ‘The Assassin Baby’

Brandon Moreno didn’t earn his nickname through some dramatic knockout or wild backstory. Instead, it came from something far simpler, his face. Moreno began training in a gym in his hometown of Tijuana as a child. At the age of 12, he devised his approach and found his footing in mixed martial arts.

When he turned pro at just 17, he still looked like a kid stepping into a world of seasoned adults. In an interview with Nina-Marie Daniele in 2023, he laughed about those early days, explaining that his teammates joked about his boyish features. That’s when the name “Baby Assassin” was born.

It didn’t take long for the moniker to stick. Regional promoters began using it. Fans repeated it. Even opponents found the contrast between his appearance and his aggression a little amusing.

But as Brandon Moreno’s reputation grew and he edged closer to global recognition, he began noticing something odd, the nickname sounded less like a fighter who hunts opponents and made him look more like a threat to babies! That realization pushed him toward a small but necessary adjustment, one that transformed the meaning of his moniker entirely.

Why Brandon Moreno changed his original ‘Baby Assassin’ moniker

Instead of being the baby in the equation, he became “The Assassin Baby,” a fighter with a youthful look but a dangerous style. The updated nickname also matched his growth. Moreno still had a friendly, upbeat personality, but inside the cage he fought like someone who refused to break. 

Over time, that blend of boyish charm and relentless grit became part of his identity. It’s why fans embraced him. It’s why the nickname stuck. And it’s why Bruce Buffer’s booming introduction still gets a reaction every time he calls out those three unforgettable words.

Nevertheless, that’s not the only captivating piece of trivia from the Mexican star’s childhood. While many are aware of several stories about Brandon Moreno’s professional life, do you know that he worked making piñatas in his childhood to help his family? Yup, that is actually true. Moreno mentioned in an interview with ESPN that, during his adolescence, he paused his studies to help his father make piñatas.

It was 2011, and he was just beginning to generate his income, not only for academic subjects, but also for attending a local gym and preparing for what would later be his life: mixed martial arts. Nevertheless, a part of his childhood still lives in him since the Mexican fighter is a huge fan of Pokemon. The two-time UFC flyweight champion has a truly impressive collection of Pokemon cards.

Another amazing fact about Moreno is that he has never suffered a TKO or submission loss. With an impressive MMA record of 23-8-2, ‘The Assassin Baby’ is one of the select few who can claim that despite over five losses, they have never been finished in a fight.

Nevertheless, his fan-favorite status came under serious scrutiny when he almost got involved in a doping issue. A few years ago, Moreno tested positive for clenbuterol from an in-competition urine sample. While many thought that this would diminish the UFC star’s legacy, USADA soon came out with the clarification that Moreno tested positive for the drug due to the consumption of meat that contained the same.

The scare faded, and his reputation stayed intact. Now Moreno prepares to face Tatsuro Taira at UFC 323, carrying the same nickname he earned as a teen, playful on the surface, gritty at its core.