Kaya Kikuma hails from Kesennuma, raised by her aunt after her parents passed away in childhood. Three years before the main story, she moved to Sendai and took on part-time work following the disappearance of a childhood friend in the sinking of the fishing vessel "Shotomaru".

Now 18, she serves as the oldest member and sub-leader of the idol group Wake Up, Girls!. Her initial decision to join was casual, intending to leave if bored, but she grew fiercely dedicated. Kaya presents a blunt, sometimes aggressive personality, often contrasting more comedic members. Despite this edge, she demonstrates maturity and responsibility, prioritizing others' welfare as the group's eldest. Her outlook evolves significantly, shifting from passivity to optimism and ambition, becoming more encouraging and gentle.

Physically, Kaya possesses mid-back length wavy dirty blonde hair, green eyes, and stands 164 cm tall. Her designated image color is green, and her associated animal motif is a crocodile.

Key relationships include doting on the youngest member, Minami Katayama, whom she finds endearing, and forming a closer bond with Miyu Okamoto through shared activities like radio shows. She maintains a competitive dynamic with rival units, notably I-1 Club's Moka Suzuki, though she struggles with games like finger guessing. Within her group, she frequently challenges the manager and agency president over their unconventional methods.

Her narrative spans all main anime entries (*Seven Idols*, TV series, *Shadow of Youth*, *Beyond the Bottom*, *New Chapter*), featuring pivotal scenes like delivering the resonant line "Do you have any regrets?" in *Beyond the Bottom*. She also appears in spin-offs like *Wake Up Girl ZOO!*, performing a solo version of "WUG Zoo Zoo" and participating in short voice dramas.