Due to her pampered upbringing, Kaya is proud, spoiled, and vain. She has a strong sense of entitlement and expects her desires to be fulfilled without question, often showing little regard for the feelings of others.

Her arrogance can lead her to extreme actions, such as orchestrating Miyo’s kidnapping to force her to give up her engagement to Kiyoka Kudou. She particularly enjoys being cruel to Miyo, having been raised to believe she is inherently superior and above those around her.

Kaya was born to Shinichi and Kanoko when Miyo was about three years old. From an early age, Kaya demonstrated her Spirit-Sight, which her parents discovered when she was only three. Growing up, she was doted on and spoiled by both Shinichi and Kanoko, which reinforced her sense of entitlement and superiority over others, including Miyo.

As Kaya matured, her spoiled nature became more evident. She would command Miyo to perform tasks, such as making tea, while speaking poorly of her with Kanoko in front of Shinichi. In a pivotal moment, Miyo witnesses a conversation where Shinichi explains that Kouji will marry into the Saimori family and take over, with Kaya as his bride. This decision sends Miyo away to live with the Kudou family and prepares her to marry Kiyoka Kudou, leaving her upset and highlighting the stark contrast between her own mistreatment and Kaya’s privileged life.