Aiko Onigiru

Aiko Onigiru is the tenth wife/cousin of Saito and the mother of both Kasiada and Kazuko Onigiru.

Aiko's backstory has been retconned in the second season from the first season. In the second season, Aiko only appears in Kasaida's dreams and flashbacks of the time when she was with her. In the first season, Aiko willingly married Saito.

Appearance
Aiko has been described by her daughter as being the most beautiful. Before Saito raped her and gave birth to Kasaida and Kazuko, she had a somewhat slender and mournful appearance. She also has silver hair, like her daughter, and purple eyes. She's usually seen with her hair tied up in a ponytail.

Aiko wears a long white and red kimono with short white sleeves.

Personality
Despite her innocent and meek appearance, Aiko has shown signs of a strong pride. This is shown in an infamous dispute she had with Akisa about Saito, where they argued about who he truly loved. This could be a bit surprising as she is usually portrayed as a meek, quiet person who is constantly in poor health.

True to this, Aiko's mind has been torn apart due to the betrayal by her husband. At the revelation that she was used merely to produce a child out of incest, she would have fits and psychotic episodes, where she couldn't differentiate between identities and lost sense of the present.

However, she had moments where she was gentle with her daughter, resulting in Kasaida's view as a child that it was just her and her mother alone in the world.

History
Due to her beauty, Aiko was lauded among the Oni's as the 'White Rose'. In the retcon, she was happy to become Saito's bride, but was then disgraced — she knew even before marriage that Saito had researched her. Following Kasaida and Kazuko's birth she started to lose her mind because of the realization that her husband never loved her.

A possible explanation for this is in the first season, it is strongly implied that Saito locked Aiko up and broke her down mentally, causing her to go mad.

She explains to Kasaida the circumstances surrounding her marriage to Saito as she lies dying. It is revealed that she knows she was being used, but loved her husband nonetheless. She also tells Kasaida that she loves her before dying. There is a realization that Aiko has been nothing but a victim of one of her husband's experiments.

She is described as having a ghost-like presence.

Saito Onigiru
To further complete his plans, Saito turned to his cousin, who calls him "nii-sama". deceiving and seducing her into believing he truly loved her. When she realized the true nature of their marriage, the conflict between her emotions broke her down and caused her to go insane. Despite this, she still loved her husband.

Kasaida & Kazuko Onigiru
Aiko loved both her children and doted on them. Her insanity caused her to have fissions in her personality: she could be gentle and meek one moment before becoming spiteful and malicious the next.

She has always begged her daughter to kill her and her husband - to the point of even giving her a silver knife that can kill Oni's. Kasaida herself has never been able to fulfill her request to end her suffering because she loves her mother and so she is tormented by guilt. Aiko often had fits when she was alone. She would worry about Kasaida and desire her presence; but because she was unstable, whenever she saw her, she had even more fits. This was because Kasaida looked like her beloved cousin, Saito.

Trivia

 * Her name is from the Japanese 愛 (ai) meaning "love, affection" and 子 (ko) meaning "child", as well as other character combinations.


 * She sometimes calls Saito "Onii-sama."

Quotes

 * "You are such a gentle girl." (To Kasaida)


 * "The only person he loves is me!" (To Akisa)
 * "And I was happy to become his wife."