Yuzuki attends Roman Academy, where she is a second-year student alongside Chiyo. Though she seems completely unaware of the social norms around her, she is frequently recruited for extracurricular activities, such as school events, music performances, and sports teams, due to her natural athletic ability and exceptional voice.

Her relationship with Nozaki’s manga world begins when he observes her behavior and uses her as the template for Oze, a loud, troublesome character who constantly causes problems for others much like Seo in real life. Though she has no involvement in manga production, her actions frequently influence Nozaki’s writing indirectly.

Seo has medium-length reddish-brown hair, usually worn down with long bangs that frame her face. She has sharp, narrow brown eyes, often giving her an intimidating or mischievous look. Her facial expressions are typically blunt or unreadable, reflecting her emotional insensitivity.

She wears the standard Roman Academy female uniform a gray blazer, red ribbon tie, and plaid skirt often with a relaxed and informal touch. Despite her rough personality, she carries herself with casual confidence and energy.

Seo is bold, loud, and completely lacking in social awareness. She often says exactly what’s on her mind whether or not it’s appropriate and has a habit of offending people without ever noticing it. She’s brash, unfiltered, and incredibly dense when it comes to emotions, relationships, and how others perceive her.

That said, Seo is not malicious. Her insensitivity stems from a lack of self-awareness rather than cruelty. She is fiercely loyal to her friends, especially Chiyo, and will help others when asked even if she does it in the most chaotic way possible.

Her hidden talent, however, lies in her angelic singing voice. Known to some as the mysterious and beautiful “Lorelei of the Glee Club,” Seo sings in public performances, leaving audiences stunned without ever realizing the impact of her own voice. Ironically, most people don’t realize the Lorelei and Seo are the same person, because her personality is so wildly different from her singing.

• The Social Wrecking Ball
  Seo’s role is largely comedic, often acting as an unintentional disruptor in the lives of those around her. Her interactions with teachers, classmates, and club leaders almost always end in frustration except for her, as she remains blissfully unaware of the damage she causes.

• Lorelei of the Glee Club
  Unbeknownst to most of her peers, Seo is the voice behind the nickname “Lorelei,” a name given to a mysterious singer in the school’s music performances. Her voice is so moving that it leaves a lasting impact on listeners, including Wakamatsu, who becomes infatuated with Lorelei without realizing that she is, in fact, Seo.

• The Wakamatsu Chaos Arc
  Seo’s relationship with Hirotaka Wakamatsu is a major subplot in the series. She constantly bullies and stresses him out in daily life, leading him to seek comfort in the voice of Lorelei unaware that the woman soothing him is the same one tormenting him. This misunderstanding is one of the funniest ongoing gags in the series and highlights Seo’s chaotic duality.