Koizumi

She is a beautiful girl with charming, long wavy hair described as having the color of kansui (alkaline water) rather than blonde.

Despite her delicate and slender frame, she possesses a voracious appetite that contradicts her petite physique, though she remains completely unaware of her own capacity for eating large quantities.

Koizumi is generally quiet and fundamentally disinterested in anything unrelated to ramen.

Her severely lacking social and cooperative skills resulted in her having zero friends after transferring schools just a few months before the story begins.

She is indifferent to both male and female attention, coldly turning down anyone who tries to flirt with her.

However, when ramen is involved, she will willingly spend time with anyone, including complete strangers or acquaintances she usually keeps at a distance like Yuu Ohsawa.

Despite her standoffish nature, she shows a surprisingly nurturing side on occasion, such as protecting a lost German girl named Hana until her mother was found, or playing in a sandbox with Misa Nakamura's little brother.

Her knowledge and dedication to ramen are unrivaled, driven by an impulsive passion that makes her travel instantly to distant regions just to try a local specialty she suddenly craves.

Her entire diet is centered on ramen, supplemented only by side dishes available at ramen shops like rice, gyoza, and even desserts.

She applies a broad definition to her passion, loving not just traditional ramen but derivative noodle dishes like chilled Chinese noodles, dandan noodles, Cantonese noodles, and champon as distinct categories of ramen.

She frequents any establishment that serves ramen, from dedicated shops and Chinese restaurants to conveyor-belt sushi chains, family restaurants, and diners, always making the ramen the star of her meal.

Her ramen journeys have even taken her overseas, such as eating ramen at a major hamburger chain in Hawaii that does not offer the dish in its Japanese locations.

Her energy metabolism is so high that skipping breakfast causes her to collapse from exhaustion by noon.

She enjoys spicy ramen varieties even though she does not handle extreme heat particularly well.

A paradoxical quirk exists between her eating and cooking skills: while she is an expert at eating, she is a terrible cook who fails at even simple tasks like preparing instant bagged noodles.

She has no awareness of her own huge appetite and therefore never intentionally challenges large-portion eating menus.

When she discovers a restaurant she likes, she will return repeatedly until she has memorized every detail of its operation, though her enthusiasm sometimes leads her to show up on regular holidays by mistake.

She holds a matter-of-fact, unsympathetic view on ramen queue etiquette, coldly chiding Yuu Ohsawa for protesting when a single person holds a spot in line for a whole group.

One of her kindest traits is her ability to perfectly identify a specific shop and menu item based solely on someone's vague, fragmentary ramen memories, which she then guides them to revisit.

Academically, she is generally a top performer, though she once had to take a makeup exam after a ramen trip to the Tohoku region left her too exhausted to perform well on tests.

She is also fluent in German for reasons that remain unknown.

Despite her extreme dietary biases, she retains a conventional sense of seasonality and local taste, cooling off with chilled ramen in summer and eating takoyaki when visiting Osaka.

In the drama adaptation, she becomes a familiar face to several ramen shop owners and is occasionally consulted, albeit passively, on new menu ideas.