Kōtarō Yui is a 27-year-old adult male with a striking appearance marked by vibrant pink hair styled in a ponytail and matching pink eyes. Standing at 180 cm, his June 1 birthdate places him under the Gemini zodiac. A pharmacist by profession, he carves out his expertise in drug composition, recognized widely as a genius within his specialized field. His communication style leans into eccentricity and unpredictability, cementing his role as the most unconventional member of his squad. Despite his flamboyant aesthetic, he embodies a rugged, assertive demeanor that positions him as the most traditionally masculine figure among his peers. Relationships, personal history, and narrative evolution remain undefined in existing records.