A teenage boy who's home alone for a week while his parents are out of town. The whole visual novel centers around him being alone and having sex with the main three girls.
- All Men Are Perverts: Everything starts because he starts abusing his newfound freedom to have sex with women.
- Childhood Friends: With Saki. They've known each other since they were little, which is part of the reason why Subaru is annoyed by her presence.
- Curtains Match the Window: Light brown hair and light brown eyes.
- Everyone Has Standards: He can't stand bullies, which is why he always rushes to Maika's rescue.
- Hates Being Touched: He gets annoyed when the three girls become physically clingy.
- He Who Must Not Be Seen: He only appears in CGs towards the end.
- Ignored Epiphany: In the neutral ending, he eagerly wonders if he'll have sex with the fourth girl that he's going on a date with. He fails to realize that his sexual desire is what made the other three women obsessed with him.
- Jerkass: He's arguably one of the more unlikable protagonists in visual novel history. He places his own desires before other's needs, uses three women to satisfy his sexual appetite, relies on Saki and Maika to do his cooking, and is disrespectful towards the women he has sex with when they express a desire for a more meaningful relationship. Some players find it easy to blame him for what happens to him in the various endings.
- Jerk with a Heart of Gold: Despite him being a perverted jerk, he's willing to step in to help Maika whenever she gets bullied.
- Loose Lips: There are times where he unintentionally lets a few things slip when he's thinking. In Yuumi's Bad End, he says that he wants to get away from her. Unfortunately, she hears him and kills him in retaliation.
- Lust: His greatest fatal flaw. He wants to have sex and he's willing to woo and manipulate girls to get it.
- Manipulative Bastard: His first encounter with Saki involves him flirting with her and using her feelings to get her to have sex with him.
- My God, What Have I Done?: In the good ending for Yuumi's route, he's horrified after he violently stabbed Yuumi to death.
- Oblivious to Love: He doesn't realize that he's made his love interests fall for him.
- Sempai/Kohai: The senpai to Maika's kohai.
- Student/Teacher Romance: He briefly pursues a relationship with Yuumi, one of his teachers. Unfortunately, things get out of hand.
- Too Dumb to Live:
- When Yuumi starts ringing his doorbell and pounding on his door, he doesn't bother calling the police and get her arrested for harassing him. What's more is that during her endings, he chooses to go outside when the doorbell starts ringing again.
- If you choose to hear Maika out in the final part of the novel, Subaru will ignore the deranged look on her face.
- Ungrateful Bastard: He considers Saki useless for not making him lunch, even though she made him breakfast the day after they had sex.
- Villain Protagonist: He finds his parents annoying, he uses his three love interests to relieve his sexual urges and he isn't interested in pursuing a relationship with any of them. Before he has sex with Saki, he even considers forcing himself onto her if she wouldn't comply.
A girl in Subaru's class as well as his childhood friend. When his parents leave for an out-of-country trip, she helps him by doing some chores for him since his mom "asked" her.
- Affectionate Nickname: She calls Subaru "Subaru-chan".
- Aggressive Submissive: She's willing to submit to Subaru and do whatever he wants, but she chases away other girls and drugs Subaru so that they can have sex as many times as they want.
- Blatant Lies: It becomes quite clear as the story progresses that Subaru's mother didn't ask her to look after him.
- Big Bad Ensemble: With Kikushita Yuumi and Saito Maika, her equally psychotic rivals for Subaru's love.
- Childhood Friends: With Subaru. She's known him for years and they've lived near each since they were little.
- Childhood Friend Romance: She would be more than happy to become Subaru's girlfriend if he actually viewed her as more than a friend.
- Dissonant Serenity: In one of Yuumi's and Maika's endings, she looks rather content after she cut up the body and is cradling a body part while she's covered in blood.
- Dude, He's Like, in a Coma!: Once in the main story, Saki wakes up Subaru by performing oral sex on him. In her Normal and Good Ends, she's still having sex with him while he's passed out.
- Entitled to Have You: Since she was the first girl to have sex with Subaru and she's known him for years, she feels like she should be Subaru's girlfriend.
- Feminine Women Can Cook: She primarily makes Subaru's meals for most of the visual novel.
- First Girl Wins: She's the first girl that Subaru had sex with and she's the one who survives and gets Subaru in most of the endings. In one ending for Yuumi and Maika, she appears on the scene to help dispose of the body and it's implied that Subaru is forced to be with her under the threat of being killed by her. In her own normal ending, she manages to trap Subaru in his own house and intends to take care of him for the rest of his life.
- I am a Humanitarian: Like Yuumi, Saki has a taste for human flesh. However, it only extends to eating her dead rivals in some of their endings.
- Murder the Hypotenuse:
- When Subaru goes on a date with another girl, Saki doesn't hesitate to kill the girl.
- In one of Yuumi's and Maika's endings, she mentions that she would have happily killed her rivals for Subaru.
- Older Than They Look: She looks like a little girl due to her childlike appearance and height. However, she's supposed to be the same age as Subaru.
- Precision F-Strike: She normally has a clean mouth for most of the novel. However, in some of the other endings, most notably for Yuumi and Maika's, she uses strong words like "bitch" and "fuck".
- Properly Paranoid: She and Subaru think it's strange for Yuumi to want to make a home visit.
- Sex Equals Love: She believes that since she had sex with Subaru, that means that he loves her. He did seduce her and made her think that he loved her.
- Weapon of Choice: A chainsaw.
- You Gotta Have Blue Hair: She has purple hair.
Subaru and Saki's homeroom and Japanese teacher.
- All Women Are Lustful: She's the most lustful of all the love interests. Her Worst Ending involves her having sex with Subaru most of the day. Her libido makes it impossible for Subaru to get away.
- Beauty Mark: Under her left eye.
- Big Bad Ensemble: With Miyauchi Saki and Saito Maika, her equally psychotic rivals for Subaru's love.
- Buxom Is Better: She has the biggest bust size in the visual novel.
- Hot Teacher: Her primary CG shows off her well-developed body. Considering that she's an adult and the rest of the cast are teenagers, it makes sense.
- I am a Humanitarian: In her Bad End, she kills Subaru and eats him.
- Kubrick Stare: She pulls this off startling well.
- Manipulative Bitch: She regularly gives Subaru detention so that she can some alone time with him and she makes a "home visit" so that she can find out where he lives.
- Pet the Dog: Even though she's jealous of Maika and Saki, she was willing to help Maika when she sees her getting bullied.
- Stalker with a Crush: Even more so than Saki and Maika. One night and even during her endings, she spends all night outside of Subaru's house, waiting for him to answer.
- Teacher/Student Romance: She's involved with Subaru, one of her students. However, after she has sex with him, her feelings for him turn into obsession as her pursuit for him becomes more aggressive.
- Weapon of Choice: A kitchen knife.
A first-year student who frequently gets bullied by other girls.
- Apologises a Lot: She apologizes whenever she gets nervous. When she accidentally spills her lunch on Subaru, she repeatedly apologizes, much to Subaru's annoyance.
- Because You Were Nice to Me: The reason why she's attached to Subaru is because he saves her from bullies.
- Big Bad Ensemble: With Miyauchi Saki and Kikushita Yuumi, her equally psychotic rivals for Subaru's love.
- A Date with Rosie Palms: In one of the alternative scenes, she says that she masturbated while thinking about Subaru and mixed her release in the food she prepared for him.
- Feminine Women Can Cook: Like Saki, she likes to cook. She frequently provides Subaru with a lunch, especially when he just drops by to have lunch with her.
- Nightmare Fetishist: There is so much in her Worst Ending that you need to check out the Nightmare Fuel section to see it.
- Ransacked Room: Subverted. She breaks into Subaru's house to rearrange the furniture... for some reason.
- Rapunzel Hair: Long black hair tied in a ponytail.
- Self-Harm: The later half of her route reveals that she's a masochist.
- Sempai/Kohai: The kohai to Subaru's senpai.
- Shrinking Violet: She's very shy and doesn't speak that often. She's also a victim of bullying.
- Weapon of Choice: A box cutter, which she uses to cut herself.
A popular girl who asks Subaru on a date in the neutral ending.
- Hime Cut: Her bangs are cut like this.
- I Can't Believe a Guy Like You Would Notice Me: Gender-flipped with Subaru. Subaru is surprised that she wants to go out with him.
- Nice Girl: She's implied to be one.
- No Name Given: Subaru never reveals what her name is.
- Satellite Love Interest: Not much is known about her character other than she's popular with other guys.
- Unknown Rival: To Saki and the other girls. It's all thanks to Subaru that she dies.
- We Hardly Knew Ye: She's only present in the neutral ending only to be killed by a jealous Saki.
- Yamato Nadeshiko: Subaru considers her a traditional Japanese beauty based off on the outfit she wears for the date.