Kumiko is a middle-aged woman, with long black hair, and dark violet eyes. She wears a white long-sleeved shirt, purple pants, and black shoes. She usually wears an annoyed expression to hide her real feelings.
Kumiko's motivations are hard to understand. In her words, she is, "A weak mother." She pushes her daughter away, partly out of anger and partly because she does not feel that she is prepared to be her mother.
She used to be a happy-go-lucky woman who was overenthusiastic about life. But when raising Haruka proved difficult due to her supernatural ability to read minds and her husband gradually ceased to come home, she buckled under the pressure. She became openly bitter, and due to her drinking in the final episode we learn that she is an alcoholic. She was difficult with her father as well, acting like a brat.
While she is a weak woman, we can also conclude that, at the core, she tried to do good.
Kumiko was born and raised in a wealthy family, at some point, her mother died.
At some point of her life, she married her future husband, and nine months later, she gave birth their first and only daughter, Haruka. They were a happy family for a short time, but eventually Haruka's ESP began to manifest. At first, there were no problems. Once Haruka began to read the minds of those around her and blurt out what they were thinking as she didn't know any better or thought they said it out loud, it began to tear the family apart. The breaking point was when Haruka exposed both parents for cheating on each other, with her mother doing it to get back at her husband for cheating on her first. After that, it is implied that Kumiko and her husband had divorced. Because she felt she was a weak mother as she was unable to help her daughter control her psychic ability, and also out of anger at herself for becoming no better than her ex husband by cheating on him when she found out his own infidelity and her daughter suffered because of their actions with her powers showing her what they've done, she pushed her daughter away, acting like she hated and blamed her when none of it was her fault as she wanted her daughter to hate her so she wouldn't be attached to her, as she feels she's deserves better than what her mother has become. She sealed it by saying, "I should have never given birth to you." While Haruka thought her mother hated her and blamed herself for the family falling apart, Kumiko was in tears and silently apologized to Haruka for being a weak mother, and blames herself for the family falling apart and Haruka's suffering.
Little is known about what Kumiko did after that. She dated at least one man after that; based on her conduct it is easily presumable that she dated others as well. She also dealt with self hatred after what she did to Haruka when she left and what happened between her and her ex-husband, while she blames Haruka for the divorce and calls her a freak, she was actually blaming herself as she knows Haruka never asked to be born with her powers, and that her ex husband was the one responsible for the destruction of their family as well as herself for stooping to his level by cheating on him instead of divorcing him when she first found out. It's speculated that she found out Haruka's struggles in school with her peers and teachers and because of her daughter's kind nature that she doesn't stand up for herself, Kumiko came back into her life and acted abusive so she can get her daughter to truly hate her and finally fight back against those that call her a monster, but tries to keep her distance as she doesn't want to get attached to Haruka and ruin her life as she did when she was a child.
At one point, she observed Haruka with her friends, but was still apathetic to her and would not meet or forgive her, stating to the Head Priest that if he were to get any closer to Haruka she would ruin his life, just as she did Kumiko's.
Despite Kumiko's cold and bitter front, at the hotel/restaurant when Haruka is there with her friends, Kumiko throws a punch at Manabe when he talks about spending the night with her daughter. Kumiko scolds Haruka, telling her that liking a pervert such as him is bad taste. After realizing she'd let her motherly instincts shine through, she quickly left.
In the last episode, she was waiting in Haruka's apartment for her. She started out overbearing and controlling, drinking a great deal and being cruel to Haruka. But after being fed up, Haruka stood up to her. She tried to hit her daughter, but Haruka predicted it and ducked. She pushed her mother back, and she fell on her bed. They both picked up a pillow and tried to bludgeon each other. After a time, both grew tired of it and made up in a way. Soon after, she fell asleep. She dreamt of the night she left Kotoura, and it is revealed she cried and called herself a weak mother and blamed herself for what Haruka suffered. She said to herself over and over, "I'm sorry, Haruka." The next morning, she had left. But she made for her daughter Over-Easy eggs, which she made the first time Haruka's mind-reading manifested. In the credits for the finale, she is shown again with Haruka, eating in her apartment, this time in a civil manner with Kumiko being embarrassed by Haruka seeing her eat the food her daughter made.
In the begining, the two had a very good mother-daughter relationship. But after her daughter Haruka's power reared its head, she became very conflicted and anxious as her daughter blurts out other's thoughts by accident. She at first tried, in vain, to find out what was happening with her daughter, but after any logical reason was proved false along with Haruka accidentally telling her and her ex husband about their affairs, Kumiko left her daughter out of anger with herself as she felt useless to help her daughter and became a terrible woman because she wanted revenge against her ex husband by cheating on him like he did her, which eventually turned her into a terrible mother. Kumiko always felt guilty, from the moment she left, and it's possible she acted abusive towards Haruka to make her hate her as she knew it wasn't Haruka's fault she had her powers, and possibly learnt of the hatred and abuse she suffered in school by her peers and teachers for her powers and wanted to harden her daughter so she can stand up against those who bullied her by first standing up to her. Which is possibly why she said those horrible things to her and why she went into her apartment uninvited and insulted her until Haruka pushed her and they fought. As Kumiko started to distance herself less from Haruka that night, It seems that the two repaired, or at least began to repair their relationship, during their second meeting.
"I should have never given birth to you."
"I'm sorry, Haruka!"
"I'm sorry I was such a weak mother!"
- Based on the state of her house in the first episode, it can be presumed the family were wealthy since when Kumiko was a little girl.
- The name Kumiko means "eternal, beautiful little girl."