|Strength||Dependent on Physical Education|
- Main Article: Intros
At the beginning of the first intro, she has a dream about her ideal lover, who she calls "Senpai", after expressing how disappointed she is with her love life in her first year of high school. That morning, because her imagination is running wild, she loses track of time and goes off to school late. She runs into someone who looks almost identical to the person she saw in her dreams. When she sees him, she instantly falls in love with him, concluding to herself that it must be fate that they met. She then sees him being scolded by his childhood friend, Osana Najimi, and plans to get rid of her.
Yandere-chan then meets a mysterious girl named Info-chan, who asked by phone to meet her in Classroom 3-3. Info-chan tells Yandere-chan about the panty shot system and asks her to kill others around the school so that her newspaper will sell better. Yandere-chan has serious doubts about this, not wanting to do anything that horrible, but Yandere-chan considers the idea after being told that Osana will confess her love for Senpai that Friday. Even so, it will still be up to the player to decide her fate.
This cutscene is no longer in the present game and is outdated. However, in the August 15th, 2015 Build, there is a visionary scene.
In the second intro, Yandere-chan is talking to herself about Senpai. Yandere-chan says she had felt no emotions at all until she met him, and now feels envy and rage towards someone who is apparently trying to take him from her. Yandere-chan says she wants to kill this person, and that there is not a single thing she would not do for Senpai.
Info-chan then sends Yandere-chan a text message, having seen her stalking Senpai. Info-chan informs Yandere-chan that the girl's name is Osana Najimi, when she plans to confess to Senpai, and about the panty shot system. The two become allies after this, though not friends as their relationship is purely client and provider.
- Main Article: Customization
Yandere-chan has fair skin, long black hair that is tied into a high ponytail with a bang swept to the left with two strands of hair reaching her shoulders. She has grey eyes. She is 165 cm tall (5 feet, 4.96 inches), weighs 43.5 kg (95.90 lbs),  and has average-sized breasts. She's seen wearing a white and navy blue uniform shirt with a red mini scarf, a matching navy blue skirt, black stockings and black shoes. Her uniform can be customized. In all uniforms, she wears her signature black thigh-high stockings. In the future, she may gain a new ponytail which will be very similar to her current hairstyle, but is an original asset.
If she has murdered a student, her uniform and the rest of her body will become bloody. When visibly insane, Yandere-chan will become hunched over, twitch erratically, have dilated pupils and the top half of her face will cast a dark shadow.
There used to be an Easter Egg where if she ran behind the Confession Tree located at the back of the school, she would be wearing a red and black version of the default uniform. This, however, was removed, after being reported countless times as a "bug".
There are several other Easter Eggs that alter her appearance, those being 47 Mode, Bad Time Mode, Bancho Mode, Blade Hair Mode, Cirno Mode, Cyborg Mode, DK Mode, Ebola Mode, Falcon Mode, Galo Mode, Hateful Mode, Punch Mode, Huntress Mode, Punished Mode, Slender Mode, Titan Mode, Tornado Mode, Witch Mode, X Mode, Hunger Mode, Medusa Mode, Gazer Mode, and Yandere-kun. The Easter Eggs that don't alter her appearance are Bad Romance Mode, a mode where a Stand from JoJo's Bizarre Adventure follows the player around, and Spooky Mode, a mode where every female NPC turns into a skeleton.
The player can also change her appearance by altering the streaming assets folder. The player can give her different hairstyles by pressing the H key. The player can give her eye-wear accessories using the P key. They can also give her random miscellaneous accessories using the O key. The < and > keys decrease/increase her bust size.
In the final game, Yandere-chan's hair will not be customizable during gameplay.
"Ayano Aishi is the protagonist of Yandere Simulator. She is known as "Yandere-chan" to players of the game, and has been given the cute nickname "Yan-chan" by her classmates.
Since early childhood, Ayano has suffered from an inexplicable, incurable condition. In short, this condition leaves her with a perpetual sense of being empty, hollow, and incomplete. As a result, she has never been able to experience satisfaction, fulfillment, or happiness, and has not been able to experience emotions in the same capacity as other people. As she grew older, she learned to pretend to be a normal person in order to avoid drawing negative attention from others, but was never able to feel any degree of empathy towards other human beings.
On the first day of her second year of high school, Ayano came into physical contact with "Senpai". In that moment, she gained the ability to experience everything that had been missing from her life; she felt complete, she felt fulfilled, she felt powerful emotions. Meeting Senpai was like seeing color for the first time, hearing music for the first time, and feeling warmth for the first time. In his presence, she felt overwhelmed with euphoria...but as soon as they were apart, the feelings of emptiness returned.
Within a very short span of time, she quickly became absolutely addicted to him, and came to rely on him in order to feel alive. Then, Ayano saw something horrible...something that terrified her and infuriated her at the same time. It was a young woman who clearly had deep feelings for Senpai. If Senpai entered a relationship with this girl, then Ayano might lose him forever...
Without a moment's hesitation, Ayano knew exactly what had to be done. This girl - her rival - had to be eliminated as soon as possible, by any means necessary, no matter what the cost."
Yandere-chan is, as her name suggests, a yandere; one who will go to any lengths, even murder, for her love. She suffers from a fictional type of insanity. Her behaviour does not perfectly match the definition of either a sociopath or psychopath, but she is capable of actions that only a psychopath would consider taking.
In the first intro cutscene, Yandere-chan was not inherently a yandere; she was coaxed into it by Info-chan, and was apprehensive of the idea of killing another person. She was just a lovesick schoolgirl who wanted a boyfriend. She didn't even seem to consider killing Osana before Info-chan brought it up. This personality, however, is outdated, and is stated by YandereDev himself that it does not correctly characterize Yandere-chan's true nature.
In the second intro, Yandere-chan is instead very emotionless, apathetic, and speaks with a deadpan expression. She had been this way since as far back as she could remember, before meeting Senpai for the first time. She would do anything to prevent people from obtaining Senpai, even if it meant killing them; Yandere-chan does not have the ability to feel emotions, empathy, or remorse. She does not feel guilt or shame for harming others. She knows what the general people consider to be "wrong", but she just doesn't care.
Overall, Yandere-chan is a blank slate whose personality is determined by the player's actions and choices, but all Yandere-chans have the capacity to commit each of the possible actions in the game.
Yandere-chan's "hobby" is trying to convince everyone around her that she's just a normal girl. She buys manga, plays video games, and rides a bike to project the image of a normal girl. However, she does not enjoy any of it. She isn't incredibly talkative by default and will only speak when necessary.
There may be differences between Yandere-kun's and Yandere-chan's characterizations. Yandere-kun would be characterized as sadistic and possessive. His life would be given meaning through his obsession with Senpai. Yandere-kun would view eliminating his rivals as a game, with each rival being an enemy that must be eliminated.
At the start of the game, Yandere-chan is very weak, as she has not honed any skills. However, Yandere-chan has a great amount of stamina, as she can run indefinitely and is quicker than other students. She also has the strength to take down a student in one hit and move heavy dumpsters, which can be filled with trash and a corpse, without getting tired.
If Yandere-chan reads enough manga volumes, then she is able to seduce males and females, or become numb enough that her sanity hardly decreases when killing students. She can also take classes to learn how to tranquilize a student, become stronger, run even faster, take down a teacher, and more upcoming abilities when the rest of the classes are implemented. Yandere-chan somehow knows how to mindbreak a student in at least 40 hours.
By the end of the game, Yandere-chan will be extremely strong, as she has unlocked all skills available. Because of this, only a yandere girl with supernatural powers could defeat Yandere-chan at this point.
Yandere-chan will be able to kill almost any NPC she comes across. However, there may be some exceptions to this. When police are added, Yandere-chan can't kill them because if they started dying then the school would have to be closed.
Like other video game characters, Yandere-chan currently has an unrealistically large inventory. Although she can only conceal three weapons, she can still simultaneously carry around fifteen manga novels, twelve cassette tapes, a bottle of tranquilizer, an answer sheet, a bottle of poison, Saki Miyu's bra, Ryuto Ippongo's headband, a modified uniform, a pack of cigarettes, her phone, and notes. YandereDev has stated that it's just one of those video game instances where some items take up space and others don't really matter. The player will eventually be able to view her inventory.
Yandere-chan is impressive because when a yandere has someone to protect, they will become capable of almost anything. She will not have any supernatural powers other than Yandere Vision, but even then her Yandere Vision is essentially just keen senses.
As of the April 15th, 2016 Build, Yandere-chan's giggle now attracts the attention of other students, causing them to follow the noise to its source.
As of the August 15th, 2016 Build, Yandere-chan can now kill teachers. In the same build, YandereDev implemented the "Sanity-based Killing Animation" for Yandere-chan, which makes Yandere-chan able to stealth kill students.
As of the March 6th, 2018 Build, Yandere-chan can use a mirror to adopt several different outward personas that will allow her to gain benefits from students she fits in with.
In June 2016, YandereDev pitched the idea of adding Yakuza-style hand-to-hand combat with the rivals in the future and final game, but the idea was scrapped. However, YandereDev still thinks that a hand-to-hand combat system could have an appropriate place in Yandere Simulator if the player pursues an elimination method that would result in a one-on-one duel with a rival.
In the original intro cutscene, Info-chan says "So, history is repeating itself, huh? Time to test a theory..." after Yandere-chan rushes to school after running into Senpai, and "I'm sure you could. It's in your blood, after all," after Info-chan asks Yandere-chan to murder a fellow student, suggesting that Info-chan knows about the true nature of Yandere-chan's family. According to Basement Tape #1, Yandere-chan's mother and grandmother were yanderes as well and kept their obsessions tied to the same chair. When her parents were in high school together, her father was Yandere-chan's mother's senpai. Yandere-chan's mother was a yandere girl in school, and killed a girl in 1989. YandereDev explains this in his blog post "Halloween and DLC". Yandere-chan has no siblings.
In fact, the line of yanderes goes back very far. YandereDev imagines that Yandere-chan's great-great-great-great-great-great grandmother wore a bloody kimono and wielded a knife. Most women in Yandere-chan's family want to give birth at a young age, such as 19. Yandere-chan's great-great-great grandmother was born in 1910, 107 years old in-game. It has also been a family tradition for several centuries that when an Aishi woman marries a man, the man always adopts the wife's surname. There were likely no male yanderes in the family. When a female Yandere is born, there are always slight differences between each generation; the Yanderes are not all clones. Their yandere tendencies are not more or less strong either.
It is known that when Yandere-chan was a baby, she never showed much emotion and was an extremely quiet child. While the father was worried, the mother assured him that the baby was fine.
Yandere-chan was an emotionless baby. She was mainly driven by biological impulses, such as crying when hungry. Growing up, she did not enjoy playing with toys. Her father was worried about her, but her mother insisted she was fine.
As a toddler, Yandere-chan did not enjoy the doctor visits; once she realized that "acting normal" would cause her father to stop worrying about her and stop taking her to doctors, she began acting like a normal child. She kept up the act throughout the rest of her childhood. She always found it to be beneficial to pretend to be normal, so she accepted that she would have to keep up an act for her entire life. 
When she was young, her mother would subtly teach her skills she would need in the future, such as how to properly clean up blood.
When she started school, Yandere-chan was bullied by other students, however, she only saw it an inconvenience. Due to this, she chose to maintain the façade of a normal girl to fit in. However, she always had the desire to feel complete like other children her age. Her mother once told that she would one day meet an individual who would complete her, she thought about it constantly, considering it the only important thing in her life, even considering it her one reason to continue living.
YandereDev has stated that Yandere-chan is a person who has never taken a life or harmed another person before meeting Senpai. For example, Yandere-chan tried to determine if she could experience any kind of enjoyment. She experimented by killing insects. When she discovered that killing insects brought her no joy, she decided to never experiment on animals, but it came to the same conclusion. This backstory was later slightly altered to suggest the possibility of Yandere-chan killing an animal instead of some insects, but this backstory ended with similar results. Thus, Yandere-chan does not kill for fun.
- Main Article: Senpai
Before meeting Senpai, Yandere-chan was just drifting through life without any purpose. Yandere-chan only met Senpai a few days before the beginning of the game. She changes because she no longer cares about right or wrong like she did before the encounter.
Before she met Senpai, Yandere-chan only ate to avoid an emaciated appearance, however, after she met him, she experienced a heightened sense of taste, which she uses to try meals that she experienced Senpai eating, to feel close to him.
Yandere-chan acts like a pervert toward Senpai, wanting to go into the Boys' Shower Room to admire him. Even so, what she feels isn't lust, but more like seeing color in a grey world. In fact, it might not even be romantic, since Senpai just seems to give Yandere-chan new sensations.
If she ever accidentally hurt Senpai, she would feel a mixture of depressed emotions. However, Yandere-chan is okay with mentally traumatizing Senpai in order to eliminate a rival.
If Senpai died in an accident or due to a disease, Yandere-chan would fall into a deep, deep depression. She would be in a coma-like state. She would refuse to eat, and would eventually starve to death. Also if Senpai died due to murder, Yandere-chan wouldn't rest until she was 100% sure she had killed Senpai's murderer in the most painful way possible. Then, she would gradually fall into the depression-coma.
Yandere-chan would not object to anything that would make Senpai happy, so long as it isn't another girl. Because of that, Senpai could use her if he wanted. However, if he ever insulted her, she would punish him and might even break him to fit her ideals.
If Yandere-chan ever lost Senpai's love, or if she got rejected by Senpai, YandereDev could imagine her crying over it. If Senpai was ever killed and Yandere-chan knew who did the deed, she would feel a cross between deep hatred and total, hollow emptiness. If Senpai ever committed suicide because of Yandere-chan, she would do the same.
Yandere-chan would love to one day confess to Senpai under the Confession Tree.
She might mind-break him in an ending.
- Main Article: Info-chan
It's a huge spoiler to say what would happen if Yandere-chan didn't take panty shots or kill students, which would help Info-chan. YandereDev wants it to influence some events near the end of the story.
Info-chan's attitude towards or beliefs about Yandere-chan may be affected by the player's actions.
Yandere-chan works 100% solo, excluding her co-operation with Info-chan.
- Main Article: Rivals
The rivals will never know that Yandere-chan exists (aside from Megami Saikou) and that they have a competition.  Yandere-chan is seemingly fine with eliminating them so long as she gets her crush.
Yandere-chan believes herself more worthy of Senpai's love than the rivals because when Yandere-chan saw Osana Najimi, she believed that Osana could never love Senpai like she can.
- Main Article: Ryoba Aishi
Yandere-chan is indifferent to both her parents. She believes that her mother is a kind, pure, warm, gentle, and innocent lady.  Yandere-chan's mother loves her daughter dearly because Yandere-chan is the physical manifestation of the love between herself and her husband.  Ryoba knows about her daughter's nonexistent emotions. Ryoba doesn't care about Yandere-chans lack of emotion, she told her daughter that someone would complete her one day.
If she saw Yandere-chan in a relationship, the mother would just be happy to see her daughter had found love.
- Main Article: Yandere-chan's Father
Yandere-chan is indifferent to both her parents. Her father has suspicions about Yandere-chan, but does not know her true nature. When Yandere-chan noticed that her father was worrying about her, she started pretending to be normal. Afterwards, there was no longer a reason for her father to worry about her. Yandere-chan's father eventually realized she was faking her normality but kept it to himself. Yandere-chan started to pity her father during this time.
- Main Article: Aishi Family
Yandere-chan's family is not very close, as once the women have found a male they don't usually spend time with others. Yandere-chan may not have even met most of her relatives. No one is on bad terms.
- Main Article: Students
If a student sees Yandere-chan murder many times, they will see her as a villain that needs to be defeated. They will continue to go to school in an attempt to catch Yandere-chan in the middle of a crime so that she can finally go to jail.
Yandere-chan seemingly doesn't care about the fates of the students and will get rid of them if they get in the way.
Students will not develop crushes on Yandere-chan. Hypothetically, if a boy developed a crush on Yandere-chan, she would not be affected. She would reject him while trying to "stay in character". On the outside, she would act like a shy schoolgirl who cannot accept the boy's feelings. On the inside, however, she would think of the boy as an insect who needs to be swatted.
If Yandere-chan becomes very popular, it's possible that in the future, students will stalk her, thus making it difficult to murder without witnesses.
If she had to pick some classmates to be her friends in order to be "normal", she wouldn't make friends with popular girls in order to not be noticed by too many people. On the other hand, she wouldn't want to become an outcast either, so she wouldn't make friends with delinquents or outcasts. She would make friends with the "in-between": girls who aren't popular, aren't bullied, aren't outcasts. In other words, she would become friends with normal, plain students and/or wallflowers.
According to YandereDev, Yandere-chan's motivations for befriending students are purely manipulative. Yandere-chan most likely has never had any real friends.
YandereDev is considering having Yandere-chan be able to join a group of delinquents, an idea that he wanted since way back in 2014.
- Yandere-chan's birthday is April 1st.
- Michaela Laws is the current voice actress for Yandere-chan. YandereDev stated that one of the voice actress' games was called "Seduce Me".
- Yandere-chan's last name, Aishi, is a play on words. "Ai (愛)"means love and "Shi (死)" means death.
- Ayano is a common Japanese female name, meaning (あやの）"my color" or "my design".
- Yandere-chan's model, Aoi Kiryu, can be bought in the Unity Asset store.
- Yandere-chan will eventually share the same base model as other female NPCs.
- Motoba Kirie from the manga and anime "Himouto! Umaru-chan" reminds YandereDev of Yandere-chan.
- After meeting Senpai and finding something to protect, she might play Hitman as a "virtual training tool."
- Yandere-chan has no preferred tastes regarding food, but if she was asked to name her "favorite" food, she would name Senpai's favorite food, because any food that brings Senpai happiness is a food she appreciates.
- On that note, Yandere-chan's favorite color is the color that Senpai enjoys the most. However, her signature or trademark color is black.
- Yandere-chan has never sung a song outside of school anthems.
- If Yandere-chan and Senpai grew old and Senpai died first, Yandere-chan would kill herself.
- If Yandere-chan is 17 years old and she appears nude, the game suddenly becomes a bit more lewd. Therefore, everyone's age is "????".
- If Yandere-chan had a cat and learned that Senpai was allergic to cats, she would kill the cat immediately.
- YandereDev has imagined that there are very few circumstances where Yandere-chan might be murdered, but the chances are very slim.
- Yandere-chan will most likely never become a club leader.
- Yandere-chan would most likely never deface the Confession Tree, as she would love to confess to Senpai underneath it one day.
- YandereDev thinks that Yandere-chan should eventually be able to swim and drown students in the swimming pool.
- YandereDev may implement hallucinations if her sanity is at a low enough level.
- Yandere-chan was not meant to resemble Yuno Gasai from Mirai Nikki.
- Yandere-chan doesn't see the point of fighting students non-lethally, (besides the delinquents) because they will just report her to the teachers.
- Yandere-chan appears as a guest character in the video game Crush Crush.
- YandereDev thinks that if she had a time machine, she'd go back to her first year and try romancing Senpai 'normally', fixing any mistakes she made.
- Yandere-chan would not sacrifice Senpai if it was between him and her parents.
|“|| I can't feel anything. For as long as I can remember, I've never been able to feel emotions. I pretend to be normal when I'm around other people, but on the inside, I feel nothing. It's not as bad as it may sound. I know that I'm broken, but I don't care. This is normal for me. But everything changed when I met him... ...my Senpai.
For the first time, I felt something. A strong desire. A longing. A yearning. A craving. Now I finally understand what it means to be human. To be alive. I'm addicted to the way he makes me feel. I don't care about anything else. He is everything to me. And now, someone is trying to take him from me.
She wants him, but not in the same way that I want him. She could never appreciate him the way I do. She doesn't deserve him. He belongs to me alone. She has taught me a new emotion...Rage. I want to stop her. I want to hurt her. I want to kill her.
There is nothing I won't do for Senpai. I won't let anyone come between us. I don't care what I have to do. I don't care who I have to hurt. I don't care whose blood I have to spill. I won't let anyone take him from me. Nothing else matters. No one else matters.
Senpai will be mine. He doesn't have a choice.
— Yandere-chan's monologue in the current intro cutscene.
|“|| Do I know you?
Do you have a problem with that?
The myth that if you confess your love to someone underneath that tree on a Friday, they are guaranteed to accept your confession?
Why are you telling me this?
Who are you?
I have heard rumors about you. You blackmail girls and sell panty shots to boys. Nobody knows your real name.
— Yandere-chan's cellphone conversation with Info-chan.
|“||...N-... N-no... W-wait...||”|
— When Senpai or a teacher catches Yandere-chan doing something suspicious.
|“||I can never face my Senpai again...||”|
— After Senpai telling Yandere-chan to go away.
|“||Senpai noticed me... at the worst time...||”|
— After Senpai sees Yandere-chan visibly armed.
|“||I shouldn't have let him see me like that...||”|
— After Senpai sees Yandere-chan covered in blood.
|“||Now he knows what I'm really like...||”|
— After Senpai sees Yandere-chan looking visibly insane.
|“||Now Senpai could never love me...||”|
— After Senpai caught Yandere-chan murdering someone.
|“||There's no way he could ever forgive me for that...||”|
— After Senpai sees Yandere-chan taking panty shots.
— Telling a mind-broken student to murder a student.
|“||Ugh...the disc is scratched.||”|
— After playing through Yanvania: Senpai of the Night.
|“||Good show! You have insulted a lady, I ought to take off my belt and thrash you within an inch of your life, sir! Fiddlesticks! Balderdash! Old chap! Pip-Pip! Tea and crumpets! Oh bother...Spiffing! Ta-ta! I say! Jolly good! Wot wot? Shenanigans! Cheerio~! Tallyho! There's a good fellow! Scallywag!||”|
— Phrases Yandere-chan says while wearing the top hat and monocle Easter Egg.
|“||Murders? What murders, officer? Oh, THOSE murders! Sorry, I don't know anything about any murders. I'm not a murderer or anything. I'm not well versed in murder at all! All I know is that I'm not capable of such things! Why would you ask me if I knew anything about those murders? I'm an innocent school girl! School girls can't be murderers, I just want to go to school and learn things, like every other school girl! Who has time for murdering people anyway? We have to study for exams! Murdering people would only waste precious time, especially for us school girls! Are you insinuating that girls like me can be murderers? How terrible!||”|
— Yandere-chan at the end of "Fingerprints, Gloves, Framing in Yandere Simulator".
|“|| Yes. I heard you talking with Saki. I want to help you with your problem. What is your father doing to you?|
Then what does he do when he gets drunk?
Your father is in debt?
What's the name of the business that your father borrowed money from?
I'm going to get your father out of debt.
You'd be surprised.
— Yandere-chan's conversation with Kokona on the rooftop.
|“|| Watch this video.|
I haven't harmed her...
If you ever want to see her again, you must do as I say.
Free all of your clients from debt.
For every day that your clients remain in debt, I'll remove one of your daughter's fingers. If you want her back in one piece, you must act immediately.
— Yandere-chan's text conversation with Musume Ronshaku's father.
I can't tell you.
There is one thing I'd like to ask you for.
Please meet me at my house tomorrow, before school begins. I have something important to tell you.
— Yandere-chan's text conversation with Kokona.
Yes. It's about the boy from class 3-2. The boy you have a crush on.
...I...I have feelings..for him...I've never felt this way about anyone before...and I can't bear the thought of seeing him...with anyone else...I know that this is a selfish request...but...please...don't take him away from me. Let me try to win his heart.
Don't worry...I will!
— Yandere-chan's conversation with Kokona at her house.
|“|| I'm sorry to call you here like this, but...I can't stay silent any longer. I know who's responsible for what you've been going through. Please, take a look at this photograph.|
This is the person who spread rumors about you and ruined your reputation. I'm afraid that they aren't going to stop until they've destroyed your life.
— Yandere-chan's conversation with Horuda if she offers her help.