Jougi Seki attends Okitsu High School as a member of Class 2A. His defining trait is pronounced narcissism, originating from an initial fascination with beautiful girls that shifted dramatically into intense self-admiration. He routinely wears makeup to school and openly discusses beauty products, highlighting their role in enhancing physical appearance. Beyond school, he wears women's clothing such as skirts and full ladies' kimonos; this practice is explicitly stated as unrelated to sexual orientation. He identifies as self-focused rather than gay, prioritizing self-love above attraction to others.

He possesses expertise in sewing and costume design. This practical application of his interest in aesthetics and fashion is demonstrated when he takes responsibility for creating Yukatas and theatrical costumes for class performances. While he frequently expresses mutual dislike with classmate Akane Kobayashi, their interactions suggest an underlying camaraderie or functional relationship, though the exact nature remains undefined in available materials.

Physically, he is a teenager with ochre (yellow/blonde) hair and petrol-colored eyes. He stands 1.75 meters tall and weighs 60 kilograms. His blood type is O and his star sign is Sagittarius. His sole documented hobby is himself, reinforcing his narcissistic traits. No significant character development or narrative evolution across the series, OVAs, or other media is detailed in the sources.