(If you know nothing about my already written headcanons for Samuel, I recommend you to read here)
After being a "mozo de espadas" for so long, Samuel's father returned to his homeland, Navarre, and dedicated himself to other taurine festivities. He soon became prolific at the "concursos de recortes" (No darn idea how to translate this on english), acts which instead of fighting the bull, the recortador had to instead avoid its hits by jumping above the animal or avoiding them with precision. Since little Samu and his mother assisted every single show of his, we could say the admiration bond between father and son was even bigger than that of León Naval and Que (Who would spectate most bullfights by TV).
Speaking of Querardo, we could say Samuel admired him too in an extent. They couldn't be with each other all the time except with few meetings, and in all of those Samu was impressed by his friend's bullfighting moves, and the passion for the dream he supposedly held. However it was when comparing himself when things took a sour turn. Unlike Que, Samu at that time was often meek and not very active, being more interested on looking than afar than getting into the action. His interests themselves were more "passive", as he would spend most of his time reading or drawing alone. But this had its consequences, such as being an easy target for bullies at school. It wasn't until Fermín saved him one day, that it was when Samuel realized his own lack of strength.
Gradually, it started to affect him. His father was a great recortador, his best friend would be a future matador, and even his other buddy was braver than him. Why couldn't he be stronger? What was stopping him from also standing up to danger like the rest? With such a low image of himself, it was obvious the glass of water would collapse. And it did, on the worst way possible.
If there was a thing that had always interested him, were the Encierros/Running of the Bulls of San Fermin festival, in which both men and women would defy death while running from fierce bulls across the streets. Being a spectator until now, also seeing his father participate in them, the desire of soon being able to run there started to make him excited. It was just the perfect way he could prove himself. Yet unfortunately that dream was still farther away, given Encierros were only allowed for adults (And kids his age could only run from fake bulls).
And this is where the profile split happens. On the dub, the Running of the Bulls remains that, just a dream.
"This plucky Pamplonica dreams of one day showing his mettle at the Running of the Bulls."
But on the japanese version, well...
牛追い祭で牛と真っ向から勝負したという伝説の持ち主。
"Legend has it that he went head-to-head with a bull in a bull-driving festival." (DeePL)
"He is the subject of a legend that he competed head-on with a bull at a bull-running festival." (Google Translate)
Yeah, he most likely sneaked in one of those Encierros and broke the law lol.
I think its interesting to mention the "Legend" part of the profile, because in a way it does make the credibility of this event more ambiguous. Did it really happen? Or was something invented? Hell, I could even see this as just something Samuel would invent as to look cooler by others (?
But given this is Inazuma, and the most bizarre method is always the one used... Yeah... Most likely happened. (And its this scenario which will be discussing).
Something curious to say is that since I don't fully know japanese and rely on translators, I can't 100% fully interpret the original profile; which that can get risky as there is some... Strange wording. I refer to the "he went head-to-head with a (or the) bull(s)", which could either imply:
He "fought" on the sense that he was running away from them
He fought one. Literally. Yet another Pamplona law broken. (Leave the darn bulls alone!!!)
...I'll leave this one open to interpretation. I'd rather have the first option however, the second one just adds even more salt to the huge wounds Red Matador has as spanish representation. These kids are literally hurting bulls and I hate that 😭
Either way, returning to my own interpetation...
Years ago pre-FFI, in the only San Fermin where neither the Naval or the Sanchez couldnt assist... Be it by bad luck or a personal choice, soon Samuel found himself running from the bulls that day, to the horror and outrage of everyone watching. Even if the authorities themselves soon stepped in and tried to save the child, somehow little Samuel started to show an incredible skill at running, being able to avoid both bulls or cops' hands with ease. Hell, even the spectators themselves soon found torn on screaming for the wellbeing of the child, or cheering on his unusual bravery. Even that little Samuel, stuck between possible life or death, felt in a way he had never experienced before.
But this joy didn't last forever. At some point, a clueless drunk tourist had angered one of the animals, becoming more aggresive and dangerous with its hits. Realizing the danger, Samuel was soon ready to leave and go back with mom, but noticing the bull had taken a detour as to follow a female runner made him change his mind. Eager to be known as a hero, he catched up to the chase alongside the authorities, even when the poor woman had become cornered. Before anyone could react, Samuel's desires of doing the greater good got twisted enough to do the unthinkable: Trying to hold the bull by the horns. Of course, reality hit him back like a truck, with the animal sending him off with incredible force.
However, before he suffered a fatal impact, his father Jorge ran up to catch him in the air. Seeing everything his own child had done left him speechless, but even he knew it was his task to step up as an adult. So, he went and distracted the beast, giving enough time for both the woman and Samuel to escape. But before he could be the one reaching for safety, a failed dash made him recieve an horrible hit that broke his bones apart. Even if he had enough medical staff to rescue him (Plus the same rescued woman was willing to pay any medical fees as a thank you), nothing was able to cure what the animal had caused. Jorge Mayo had lost his hability to walk.
Of course, the other parent of Samuel wasn't happy with this. She wouldn't stop bombarding her son with questions, all so she could get anything of what was going on her child's mind that way (Like I've said, him getting into the run by choice or by accident is not defined yet). Not even herself could believe her eyes, that the shy boy she had raised was willing to die like that. Moreover, regardless of Samu's reasons, Jorge step up to defend his child one last time, saying it might as well been by accident and that he had been stuck on a constant 'flight or fight' phase. Maite struggled to accept that defense, but soon enough she swallowed it up as to give herself re-assurance that Samuel was NOT that way.
Moreover, when Samuel asked his father why he had covered up his actions...
"Despite everything, what you did back on that run was increidible. I'm proud my boy has such strong guts as I, haha.
But if you ever are to test them once more, all I ask is to avoid endangering anyone"
It took time to accept it, but soon Samuel decided to live with that excuse. Even if seeing his father being unable to perform again started to accumulate quite the guilt on him. It didn't help that he did interpret the moral in his own way. For him, it wasn't "getting into the Encierros" his mistake, but his "true fault" relied on the fact that he hadn't been strong enough to fend off that bull. If he had been as strong as his father and his friends, his father would not have ended in a wheelchair. But no. Aganist that bull, he had been weak. And no matter how time went on, he was barely able to forgive himself for that.
But as to cope, he promised himself something: To become stronger and stronger until the time to face off a bull again came. Didn't matter the method, or the speed of the progress. But the meek 9 y.o Samuel would cease to exist from now on.
At least, the event had its pros. It didn't just break him out of his shell, it straight up pulverized it. From that point on Samuel became more willing to try new things, more extroverted, and in Querardo's eyes: "More cooler!!!". That being said, neither his friends nor most of the public knew what actually happened that day; buying all into Jorge's lies of all being just an accident. Nonetheless, around the streets of Pamplona, Samuel's name still spreads around as the "child who ran with the bulls". Though, comparing appearances of the boy back then and FFI!Samuel does shock most people. I mean, to think that 4-5 years before the FFI, he used to look like this:
Puberty hit right him like a bull...