The members of the Aishi Family are important characters in Yandere Simulator. The Aishi Family comes from a very long line of "yanderes".
The origin of the Aishi condition was passed down generation to generation. However, its origin is now considered a fairy tale, as Aishis stopped taking it seriously.
All Aishi born-members are nearly emotionless until they find the person who can make them experience intense feelings. For example; Aishi babies do not cry when they are born.
There will always be slight differences between each child born into the Aishi family, but never in terms of strength of their condition. At least two known Aishis, Ryoba and Ayano, had felt considerable pity towards their relatives, not necessarily making them empathetic but not heartless either.
The cruelty of the Aishi's actions to carry on their goals of maintain their new intense emotions will depend on them individually. There have been several Aishis who mind-broke their husbands, and other Aishis who avoided doing so. There had been members who are capable of finding pacifist methods, such as Ayano (according to the player's choice).
The condition that the "Aishi Family" suffers from has affected Ayano's ancestors: it has been said on the video on "Yandere Lack of Emotions" video. The condition makes them depressed, emotionless, and incomplete.
All the Aishi family members, except "The First" Aishi, and Ayano, are named after blades. If Ayano has a child, they would also have a name that sounds like a blade. Canonically, Aishis give their kids names that they think are "pretty", but behind the scenes, though, each Aishi's name has some kind of double-meaning or purpose.
It has been a family tradition for several centuries that when an Aishi woman marries a man, the man adopts the wife's surname.
Relationships between members
The Aishi family members aren't very close. Once an Aishi has found a partner, they tend to distance themselves from the family. It is likely that Ayano hasn't met most of her relatives, although no one is on bad terms.
When Aishis do meet, they probably exchanging advice on how to get away with murder. Ayano’s grandmother would help her kill and dispose of a rival if asked. However, YandereDev doesn't think she helped Ryoba.
There is a kinship among the various "Senpai's" because they share each other's experiences with a yandere partner. Still, they are all their own unique individual and how close they become with one another will depend on their respective personalities.
Relationship between an Aishi and their "Senpai"
After enough years in the presence of their "Senpai", an Aishi will eventually develop the capacity to experience emotions, even when apart from their "Senpai". After several decades in possession of a "Senpai", an Aishi would no longer require their presence in order to experience stimuli the same way that normal humans do.
A "Senpai" can influence their Aishi's personal growth and development. If their "Senpai"says "Stop killing people or I'll hate you forever!" enough times, they could "train" their Aishi to stop being a killer. If their "Senpai" is meek and submissive, then they would have no influence over their Aishi's development.
If an Aishi loses their "Senpai" before they have developed the capacity to experience emotions, they would feel as though they have permanently lost the capacity to hear music, see color and feel warmth. This may lead them to fall into an extremely deep depression that leaves them in a coma-like state. However, if an Aishi loses their "Senpai" after they are no longer dependent on their presence, they would not fall into the coma, but would still feel an extremely deep sense of loss and pain that is far beyond what a normal human would feel at the loss of a loved one.
Depending on how the Aishi "developed" after acquiring their "Senpai", they would react to their death differently. They might enter the coma-like state, might fly into a blind rage and kill everyone around them, or might try to live a normal, happy life without their "Senpai". This is heavily dependent on what type of "Senpai" they acquired, and how their "Senpai" influenced their personal growth and development. It is also dependent on how their "Senpai" died. If the "Senpai" died of illness, the Aishi would feel as though nobody is to blame. If the "Senpai" was murdered by someone, the Aishi would seek revenge.
The last name "Aishi" is a play on words. Ai means "love" and Shi means "death".
All of the Aishis look almost identical to one another. YandereDev imagines all of Ayano's ancestors with the same exact hairstyle, even if it feels goofy to him.
YandereDev think it would be uncharacteristic for Aishis to believe in any religion.
Most women in Ayano Aishi's family desire giving birth at a young age, such as 19.
The first Aishi and "important" ancestor of the protagonist was born in 1780.
Her parents were somewhere in their 20s when she was born, and they aren't a part of her backstory.
She was born without any conditions, and her condition isn't really a "sickness".
YandereDev has an illustration of her, but he wouldn't like to reveal or describe her.
Due to the circumstances surrounding her life and her lifestyle, it's entirely possible she may have been forced to kill a human prior to 1797. But, if so, it wasn't a love rival; it was someone who was threatening her life.
She met "First Senpai" in 1796, but she didn't form a relationship with him until 1797.
Love between her and her Senpai bloomed naturally, and was genuine and mutual. However, they were also in a position where they had almost no other options.
A third party informed the "First Senpai" that she was in love with him.
She was born under a different surname and started using the surname Aishi since 1797, upon arriving in Japan with "First Senpai", because they had to select a name that the locals could pronounce more easily than their real names.
She did not wear traditional Japanese clothing until she arrived in Japan. Her "color scheme" was always red+white+blue, like Ayano's default school uniform.
The first time she had an encounter with a "love rival" was in 1797, and that's when for the first time she'd take a life. However, when she took lives in 1797, it was all entirely in self-defense, including the "love rival" that she faced at this point in time.
She had to deal with one, technically two rivals to win her "Senpai".
There is an Info-chan-like figure in First Aishi's life.
The amount of her murders depends on whether or not self-defense is considered murder. Depending on the criteria for "murder", the answer is either zero or hundreds, and only a fraction of those deaths took place in Japan.
There probably wasn't an "official" wedding between her and her Senpai, but they did consider themselves husband and wife.
In the Edo period (1603-1868), where the first Aishi lived, there was only 4 classes in Japan society - Samurais (侍 Shi), Farming Peasants (農 Nō), Artisans (工 Kō) and Merchants (商 Shō). YandereDev has something in mind for the occupation/role that both she and her "Senpai" had performed once they arrived in Japan, but he wouldn't like to reveal it. However, he did confirmed that from this four classes, she didn't really fit into the noble class of Samurais or into the Farming Peasants class, which implies she may been either Artisan or Merchant, but he also did said that she was in "a class outside of normal society". Her Senpai belonged to the same social standing.
YandereDev imagines that Ayano's sixth great grandmother wore a bloody kimono and wielded a knife.
Ayano's great-grandma and great-grandpa were the first to move to Buraza Town. Ayano's grandma asked for a basement, which great-grandma agreed to.
Yan-chan's great-grandpa was the builder of the basement, he was mindbroken, enough to not question why he was building a basement in the first place. He was probably kidnapped and mindbroken, but not in a house. He was probably kept in a warehouse or a cave in a nearby forest.
The grandmother eventually kidnapped the grandfather and kept him in their basement. They then gave birth to Ryoba, who eventually used the basement at least once.
YandereDev thinks that Ryoba's mother may have brainwashed her husband into loving her unconditionally.
Ayano's grandma in the final game may visit to help take care of her granddaughter, and imparts advice whenever she stops by.
If Senpai is customized to be a girl, the Aishis will still find a way to continue their family line. It has not been explained how yet.
It is likely that there are no male Aishi with the condition in the family and the family line has consisted of female-only members with the condition for centuries.
While male children are unlikely, they would look similar to Senpai and would have same condition as the females have.