Kyosuke Momoi, a 19-year-old male idol in ArS, stands 171 cm tall, weighs 50 kg, and has blood type O. Born on September 28th, he possesses bright pink eyes and disheveled pink hair featuring long bangs and distinctive side tufts, often seen wearing red-rimmed glasses outside performances.

A self-proclaimed otaku, Kyosuke passionately embraces anime, games, and special effects, holding a particular admiration for heroes. His primary creative expression manifests through drawing, leading him to work as an autobiographical manga artist. He secretly sketches fellow idols—including ArS members and Death Chronos from RE:BERSERK—as reference models without their knowledge, regularly posting these illustrations online while keeping this endeavor hidden from his unit. Personality-wise, he presents a reserved front yet reveals an underlying cheerfulness. He displays notable clumsiness, such as tripping during self-introductions, and frequently battles deadlines, often appearing distressed while seeking last-minute help.

His family includes unnamed parents, an older brother, and a younger sister who shares his otaku passions. He savors chocolate but avoids oysters. Other enjoyments include interacting with fluffy animals and cooking udon dishes like Tsukimi or Kitsune udon. Socially, peers address him diversely: "Kyosuke" by most, "Kyo-chan" by Kanata and Shiki, "Momoi-kun" by Akira, "Kyosuke-san" by Chaoyang, Runa, and Wakashi, "Kyosuke-kun" by Toya, Futami, and Momosuke, and "Innocent One" by Eva.

His manga artistry draws motivation from gathering idol experiences for reference material, finding notable inspiration in Torahiko Kusakabe’s unpredictable nature. Before pursuing idolhood, Kyosuke contemplated a career in voice acting.