Ryoba Aishi

Ryoba Aishi is Yandere-chan's mother and the wife of Yandere-chan's father.

It has been confirmed from the first Basement Tape that she is the same girl featured in the Mysterious Tapes whom The Journalist confronted. She will be out of town for 10 weeks for Story Mode because she is chasing down The Journalist, as said in Basement Tape #10. She will be playable in 1980s Mode.

Background
Before Ryoba met her senpai, she was the same as her daughter. Her daughter moved through life with no purpose and thought without emotions, only logic.

Eventually, Ryoba met Yandere-chan's father in the 1980s at Akademi High. Ryoba was a yandere, and killed the Phantom Girl with a knife in the third floor girls' bathroom. As revealed by a series of tapes, her activities - using manipulation, intimidation, and sometimes even violence to bring about the disappearances and expulsions of her upperclassman's admirers - were discovered by a suspicious journalist who had taken it upon himself to investigate the murder when the police were forbidden from conducting a formal investigation. Ryoba was arrested and accused of committing numerous crimes, but was able to not only deflect the charges but sway public opinion in her favor by playing the part of an innocent girl being stalked and falsely accused. Ryoba used the court case to simultaneously become a media darling and irreparably ruin the Journalist's reputation, and after she was acquitted of all charges she cornered the Journalist and warned him to never cross her again, as it would be too easy to make his death seem like a suicide.

Soon following this, as revealed by Basement Tape #1, Ryoba abducted her upperclassman, tied him to a chair, and forced him into a relationship with her, revealing that her mother had done the same to her own crush, implying that she was a yandere too. Ryoba eventually married her upperclassman, giving birth to a single daughter at around the age of 19. She has no other children other than Yandere-chan.

She has a job related to the game's lore. YandereDev has planned to drop hints about what the job is soon. In Basement Tape #10 it is implied to be something about not being seen.

Ryoba never moved out of her home town or gave up her yandere habits, as almost thirty years after the investigation she was discovered by the Journalist stalking a young woman fresh out of high school. Realizing the Journalist had returned, Ryoba lured him into an alleyway and ambushed him. He ran away, fled Japan and left to America. Ryoba and her husband then packed their bags and went to America as well to hunt down the Journalist.

Appearance
The mother has a gentle face. She is identical to Yandere-chan but older. She has the same hair color and hair style as her daughter. When her true nature shows, her eyes are empty and soulless, and she wears a disturbing smile.

Personality
She is a yandere and a murderer, just like her daughter. In addition, she has no emotions, even when she was a baby herself.

In the original intro, Info-chan gives a hint about it when saying "So, history is repeating itself?" and "It is in your blood, after all." to Yandere-chan, though this intro is now outdated.

Being a yandere, she is clingy and paranoid, needing to kidnap her senpai even after getting rid of her rivals.

The mother seems to be willing to take serious action to get jobs done, as seen by how she dealt with the Phantom Girl. This was just out of obsession for the father of Yandere-chan. The way she took down a girl with only a knife probably means that she's tough enough to take another student down both mentally and physically.

She also seems at least somewhat cunning if she was able to murder some people, get away with her crimes, and able to kidnap the father. She was able to fool all of Japan into thinking she was innocent and that the Journalist was the villain. She must be very confident and bold to do such things.

Mysterious Tape #3 shows that she was well-rounded and could effectively bully, expel, and keep people from coming to school. Judging by the fact that she usually ran around with a mop and bucket means that she still killed people, so she pretty much used a variety of elimination methods to achieve her goal, unlike Yandere-chan who can just use one, but might not.

The fact that Ryoba never killed the Journalist during the few decades of their truce means that she isn't entirely needlessly cruel towards her goal. She left him alone instead of maliciously attacking a person who's totally helpless, and doesn't seem to kill any regular girls or boys for fun. It's possible that the methods of elimination she chose were simply the best options for her, but hated the rivals too much to actually get rid of them without hurting them in some way. All in all, she seems kind of practical, except for the fact that she kidnapped her senpai after getting all her rivals, not before.

Yandere-chan
Ryoba might have passed down her murderous traits to her daughter, though Yandere-chan doesn't have to kill anyone over the course of the game.

Yandere-chan doesn't have a negative relationship with her parents. YandereDev states that she's just indifferent to them. Yandere-chan believes her mother to be a lovely and innocent human being, though she may not know what her mother did in the past. Yandere-chan's mother loves and adores her daughter very dearly because she is a physical manifestation of the love between her and her husband. The mother knows about Yandere-chan's lack of emotion.

If Ryoba sees Yandere-chan romanticizing a female Senpai, she would be delighted to see that her daughter has found "love" with someone. Her mother gets her values from her own experiences.

Yandere-chan's Father
Ryoba's background was revealed in the Basement Tape. During the 1980's she kidnapped her senpai and held him hostage. It is revealed that she extremely loves him, while he doesn't have the same feelings for her back. She eventually married him and had one daughter, Yandere-chan.

Even after having a daughter the father is still afraid of his wife. For example, when he thinks he has accidentally said something wrong about his extremely quiet daughter, he quickly corrects himself before Ryoba can truly notice, implying that he is still extremely afraid of his wife. Basement Tape #10 proves that he doesn't dare go against her, and is submissive to the decisions of his wife.

Phantom Girl
Ryoba killed the Phantom Girl with a knife in the third floor girls' bathroom in April 1989, as hinted at in some of the Mysterious Tapes.

The Journalist
Their backstory and how they interacted is told throughout the Mysterious Tapes. There's some more information on the Basement Tapes.

The Journalist almost goes blind with rage when he sees Ryoba, though he still runs away from her after she found him stalking her after a few decades, due to the danger he would face. The Journalist's hunger for revenge has not been sated for now, but he is said to possibly appear in a secret main story mode ending, which implies that he could get away from Ryoba entirely.

Ryoba doesn't kill The Journalist right away after the court case and he lives until sometime shortly before Yandere-chan's first day of high school, as seen from Basement Tape #10. Ryoba follows him to America, but it's currently unknown what happens next.

Unimportant Woman
In Mysterious Tape #9, Ryoba was stalking a woman who flirted with Yandere-chan's father. The woman died in the next tape. She is a very unimportant character as she won't have a name or will ever be a rival.

Trivia

 * Ryoba's voice actress is Michaela Laws, the same voice actress as Yandere-chan.
 * YandereDev has not decided if Ryoba will have any siblings.
 * Her name was revealed in Basement Tape #1. Ryoba.jpg
 * The first Basement Tape may have implied that Ryoba raped her husband. When asked about this on Twitter, YandereDev said that he would like to address this issue with a tape so it would not be spoiled on Twitter.
 * The Japanese word for "matron" is "ryōbo (寮母)". The name was changed to Ryoba so it would sound more feminine. When translated, "ryōba (両刃)" is a type of Japanese saw which means "double blade" in English.
 * She never left her hometown, so it was easy for The Journalist to find her after several years, as said from Mysterious Tape #9.
 * The player might get to see Ryoba in action in a brief ending cut-scene of Story Mode, but it would depend on budget and volunteers.
 * There might be a specific cutscene between Ryoba and Yandere-chan if the latter uses pacifist methods in eliminating her rivals.