Osanai Aya, known mononymously as AYA, is a CrossFit trainer and fitness model who has competed in KUNOICHI 10 and KUNOICHI 11. In the tenth competition, she had trouble on the Double Pendulum during her run on the Red Stage, but recovered to become the fourth clear of the day, out of six total. In the Blue Stage, a tense run ended in success when she cleared with just 0.19 seconds remaining, the first clear of the stage that competition. In the Black Stage, she was the first to clear the debuting Propeller Untei and Arm Bike, making it to the Cliffhanger before failing, unable to transition onto the second ledge.
In the eleventh competition, she was given the #50 position due to her potential based on her previous result as well being the only competitor from the Black Stage in the previous competition (Watanabe Kana and Izumi Hikari could not compete due to prior commitments). She had little issue with the first few obstacles in the Red Stage, but her run shockingly ended on the Fish Bone, breaking the clear streak of the previous four competitors to end the stage.