Gaku Yaotome, a member of the idol group TRIGGER, sports platinum-blond hair and sharp features, projecting an assertive, charismatic stage persona that masks his private demeanor rooted in honesty, integrity, and fierce loyalty. Behind his polished exterior lies a vulnerability shaped by familial struggles: born into a divorced family, he discreetly assists his grandfather at a soba shop as a delivery driver, a secret kept even from colleagues like Tsumugi Takanashi. His fractured upbringing fuels his quiet dedication to preserving familial bonds, accepting gifts from his mother and grandfather while evading public scrutiny.

Interpersonally protective, Gaku forges close ties—exchanging matching shoes with Yamato Nikaido after a casual compliment and adopting a brotherly dynamic with Iori Izumi, whom he nicknames "Izumi-otouto." His subtle romantic interest in Tsumugi emerges through invitations to meals, offers to drive her home, and encouragement to attend TRIGGER rehearsals incognito, balancing support for her career autonomy with personal affection.

Practical yet introspective, Gaku collects bath powders, enjoys driving, and selects films based on directors or casts rather than genre. During emotional lows, he retreats into cryptic riddles, contrasting his usual directness. Professionally adaptable, he masters skills like guitar or rollerskating for roles, showcasing relentless dedication.

Publicly hailed as the "sexiest man alive," he privately navigates societal judgment over his family and maintains a chaste personal life despite flirtatious stage performances. Collaborative events highlight his emphasis on teamwork and fan service, framing customer interactions as extensions of his idol craft. His growth centers on reconciling authenticity with industry demands, often choosing sincerity over manufactured image.