The Gutiérrez Family is one of the most prominent families in Wizarding Spain, with an ancient bloodline that traces all the way back to medieval pure-bloods. The current patriarch is the stern and headstrong Pablo Gutiérrez, who currently holds a high position in the Spanish Ministry. He is the husband of Sofia García-Gutiérrez, a renowned actress who also comes from a pure-blood family. Together, they have two children -- a boy, Sergio, and Marina, a girl. Sergio is the older one of the two, and is also the heir apparent of the main branch of the family, so growing up, the idea of being the future head and carrier of prestige has been instilled on him, giving him a sense of entitlement, of privilege, over others. He grew up in a household where everything was handed to him, in exchange for being the poster boy of the family and doing whatever his dad tells him to do. He didn't mind much though, because he still got most of what he wanted, and as a result, became a spoiled brat.
Sergio's group of friends consists of the children of other Spanish pure-blood families, a close tight-knit group of the Iberian Peninsula's elite. A lot of the other children are in his age, and they all go to school together at Beauxbatons. They exude an air of exclusivity, and are feared by some of the other students because of how ruthless some of them can be. In essence, they were on top of the food chain, the royalty of the school hierarchy, and they got there because of their social status and their money. Sergio was happy enough with his circle that he didn't bother to make any new friends, or even bat an eye on another person's direction. He was convinced that all he needed was the members of his "Elite Circle" and he'd be able to coast through life. This would later on prove to be a grave miscalculation.
On Sergio's sixth year, after a string of problems at home because of the increasing isolation he and his sister are receiving from their parents - with their dad preparing for the upcoming elections, and Sofia shooting a movie overseas - Sergio decides to rebel a bit. His sexual life has pretty much been active at that point, having had both boyfriends and girlfriends in the past, and this is enough for a certain teacher at school who's been eyeing him for a while, to put her plans into motion and "prey" on her student. She lures Sergio into an empty classroom under the guise that they needed to talk about his grades, and successfully seduces him. This goes on for a couple more weeks, with the teacher, Katarina, immensely enjoying it, but Sergio grows more wary the more they do it. He knows it's wrong and despite the pleasure he's receiving from it, he's also not sure if it's enough to justify the whole situation. Eventually, he tries to put a stop to it, but Katarina, who doesn't want it to end, threatens to flunk him in class and starts abusing and emotionally manipulating him. Sergio manages to clue in his best friend, Enrique, who tells one of the other teachers, and they both barge into a classroom while Sergio and Katarina were doing it. Caught, Katarina is fired and sent to prison, while Sergio is expelled from school.
Sergio's parents were, of course, furious with everything that happened, further damaging their relationship with their son. He was grounded for the rest of the school year, and wasn't allowed to see any of his friends during the summer, putting him under a state of depression, which he hides by being more broody and grumpy than usual. The following term, his parents send him to Hogwarts at the United Kingdom to repeat his sixth year, and also hoping that the school is far enough that the student body hasn't heard of the scandal that unfolded back in Southern France. But alas, all secrets eventually do come out, no matter how hard Sergio tries to stop it.