| Sonoko Kashiwagi|
|Normal | Yandere|
|Personality:||Modest and Shy|
“I’ll love you forever…”Sonoko Kashiwagi (柏木園子 Kashiwagi Sonoko) is a character from the Yandere No Onna No Ko Drama CD 1.
Sonoko is a shy and polite girl who is a member of her school's gardening club.
She is the Protagonist's classmate. She fell in love with him when he defended her from other classmates who were bullying her.
When she realizes that he doesn't consider himself to be that close to her, she confines him, kills him, and uses his skull as a flower pot.
Nagisa describes Sonoko as a quiet and gloomy girl who studies with the Protagonist. Nagisa kills Sonoko offscreen.
Ayase mentions that Sonoko helps the Protagonist study. She's somewhat envious that he spends more time with Sonoko and Nagisa than her.
Despite Ayase demanding that Sonoko doesn't see him anymore, she insists on going to see him and looks for him. After this, Ayase attempts to murder Sonoko with a pair of scissors. Sonoko, having been injured, screams for help. Ayase stabs her to death as she screams to her that "ugly girls like you should die". She explains this is why Sonoko hasn't been going to school as of late.
Ayase remarks that someone "so ordinary" like Sonoko wasn’t suitable for the Protagonist.
Sonoko speaks to the Protagonist about their life in her room. She recalls the first time they met, when he defended her from schoolyard bullies, and when he consoled her in a park. Despite the fact that they weren't even friends, the Protagonist was nice to her and took up for her. Sonoko infers that Ayase is his girlfriend. She explains how she grew envious of Ayase, believing that someday he’ll break up with Ayase to be with her.
She decides that she wants Ayase to be dead, and goes to confront her at night. Even though they tried to resolve the situation, Ayase insulted Sonoko and refused to listen. Because of this, Sonoko slaughters her with a shovel. After Ayase dies, Sonoko caves the inside of Ayase's stomach so she could use her body as a flower pot.
Later, because the Protagonist wasn't coming home, Nagisa started to find Sonoko suspicious.
Nagisa starts stalking Sonoko, with the belief that she's confining the Protagonist. At one point, Nagisa sneaks into Sonoko's house to find her brother, but Sonoko decides to spare her life and kick her out. Not long after, it's revealed that Sonoko murdered the Protagonist and used his skull as a flower pot.
- Sonoko's appearance can be compared to that of Kotonoha Katsura, from the anime School Days. Both of them are reserved, quiet, well-endowed, were bullied by their classmates, they killed a girl they thought was taking the protagonist(s) away from them, and they preserved the severed head of the boy(s) they loved. She is also voiced by the voice actress who played Sekai Saionji.
- She is voiced by Shiho Kawaragi, who also voices Elise Sakuranomiya. Both Elise and Sonoko have shy personalities.