| Nagisa Nonohara|
|Normal | Yandere|
“Let’s be together forever and ever…”Nagisa Nonohara (野々原渚 Nonohara Nagisa) is a character from the Yandere No Onna No Ko Drama CD 1.
Nagisa is the younger sister of the Protagonist. She has presided over the household and does chores such as cooking and cleaning. She always cooks for him and makes lunchboxes for him.
Her feelings for her brother go past familial love; she has romantic feelings for him. She goes to drastic and violent lengths to "protect" her brother, because she believes that he'd abandon her if she didn't.
Nagisa goes out to do "something important". Because of this, she's unable to prepare dinner for the Protagonist. When she returns home, she apologizes for not being available. She then asks the Protagonist about why a handkerchief from Ayase was in the laundry. The Protagonist tells Nagisa that he got hurt, so Ayase lent it to him.
Nagisa points out that because he studies with Sonoko, he's been coming home late. She begins complaining that he spends too much time with Sonoko and Ayase, but not her. She claims that she's the only person that truly understands him.
She asks what he had for dinner, and he says he went out to eat. He says he ate alone. Nagisa smells him, and notices that he smells like Ayase. She realizes that he was lying; he ate dinner that Ayase cooked for him. This angers her, and she reveals that she killed Ayase and Sonoko. She tells him that he is "tainted" and "poisoned" because he ate what Ayase cooked. She immobilizes him by battering his legs, thus preventing him from trying to get away from her.
To "clean out" Ayase's cooking, she prepares a large meal for him. She force feeds him various dishes. She shows him the last dish: happosai. Nagisa explains that she made it because Ayase has prepared it for him before.
When he's done eating it, she asks whether her or Ayase's happosai is better. She tells him to be honest because she won't get mad, either way. He says that he prefers how Ayase prepared it. This does anger her, so she says that they'll be together forever and stabs him.
Ayase explains to the Protagonist that Nagisa was looking for and called out to him while he was at Ayase's house.
Initially, Ayase wanted to spare her, because Nagisa is his sister. She changed her mind when Nagisa began to insult her. She attacked Nagisa and put Nagisa in her room; Nagisa made an attempt to escape, but Ayase murdered her.
When the Protagonist is nowhere to be found, Nagisa becomes wary of Sonoko and spies on her. Nagisa tells Sonoko that she believes Sonoko is confining him. Sonoko denies this, as she believes he's just living with her now.
Later on, Nagisa sneaks into Sonoko's house to see if the Protagonist was there. Sonoko spots Nagisa and kicks her out, but spares her life. Nagisa never finds out what happened to her brother.
- Her physical appearance can be compared to that of Kaede Fuyou, from the anime Shuffle!. Both girls live with the protagonist, they serve/cook for them, and they are possessive.