Valeria is the only girl in her family, and the youngest among four children. As such, she grew up in an environment where the idea of machismo was very much woven into her family dynamic. The men of the family could do no wrong and were free to do as they pleased, while Valeria was expected to treat her male counterparts with the utmost respect and assist her mother around the household. This mostly translated into helping with cooking, cleaning, and other household chores while her brothers were free to pursue their own interests.
Her father served in the Mexican army, and all her brothers followed in his footsteps and pursued a career within the Mexican military. Though her parents emphasized the importance of receiving a higher education, it was always undercut with the expectation that Valeria would eventually settle down, find a husband, and start a household of her own. Rather than do what her family expected of her, Valeria joined the Mexican army and eventually became a part of the Mexican Special Forces. She is the only one among her siblings to have accomplished this.
Though her enlistment in the army was a means to break the mold of what was expected of her as a woman living in a man's world, she quickly discovered the double standard within the army. Female soldiers weren't treated with the same respect as their male counterparts, nor were they taken very seriously by their training officers. In order to rank up, Valeria had to work twice as hard and push herself beyond her limits to even be considered on a level similar to her fellow male soldiers, let alone become the leader of her own squad.
Even as a squad leader, Valeria is held to a higher standard. Her unit is 'clean cut' because if there are any mistakes, or rules broken, the blame would fall on her, and the retribution from her superiors would be swift.
The rampant sexism and corruption within the Mexican army is a large part of why Valeria eventually becomes El Sin Nombre. After years of service, with little recognition, and little to show for her hard work Valeria is incredibly frustrated with the system. It's a never ending cycle of fighting tooth and nail for a shred of respect, only to be judged for every action, every decision made, with very little progress made. She will never be enough simply because she is a woman, and the enemy they fight is too powerful, and better funded than they are. They are fighting a Sisyphean war.
Becoming a part of the cartel provides her an opportunity to gain status above anything she could ever dream of accomplishing in the Fuerzas Especiales. The power is ultimately what attracts her to switch sides, and eventually rise to the position of El Sin Nombre. Now the 'nameless' leader of Las Almas cartel she is able to reinvent herself, assume a new identity separate from her gender, and build her very own empire.
