Student Council President
|Strength||Extensive self-defense training|
She was first shown in the "December 2015 Progress Update" video. Soon after, she reappeared in a video shown by a volunteer named "YandereAni" and was implemented into the game in the January 1st, 2016 Build.
Megami has fair skin, rosy cheeks, silver eyes, and long silver hair down to her thighs with 'v' shaped bangs.
Megami wears the default female school uniform, with black stockings, gloves and a choker with red stitching and bows. She wears the "Red Armband of Leadership" on her left arm reading 生徒会, meaning Student Council written in kanji.
She previously appeared as her old appearance in a video on a Saikou laptop, that currently resides in the Student Council Room, in which she had black hair instead of her current silver hair, however now she has her current appearance.
"Megami is the heiress to Saikou Corp, the most powerful business conglomerate in Japan. She is impossibly wealthy, a certified genius, has extensive self-defense training, has excelled at everything she has ever attempted to do in her entire life, and has been trained to possess all of the qualities of a perfect leader, to prepare her for the day when she will inherit her father's company. She is also the most beautiful girl in school, the most popular girl in school, and the student council president.
Megami has been absent from school for nine weeks under mysterious circumstances that she refuses to disclose. She has still managed to keep up with her schoolwork by attending class through a laptop, and has also been able to manage the school's student council by attending meetings via video call. She is noticeably upset about this; she strongly believes that she should be attending school like a normal student, and is resentful of her current situation, although she is not at liberty to explain the reasons for absence.
Megami, unlike all other characters, is fully aware of the fact that there is a dangerous person on school grounds. Once she arrives at school, she will do absolutely everything in her power to protect the school's population - that includes installing security cameras, hiring security guards, and instating a zero-tolerance policy for suspicious behavior. Megami clearly has some very important information that would cause her to go to such extreme lengths...but what does she know? What does Saikou Corp have to do with it? And, more importantly, what does Senpai have to do with it?"
Megami is going to be a strict disciplinarian. Everyone agrees that she is mature, responsible, and intelligent. Her IQ is 140. However, some say that Megami acts as if everything she says and does has been written in a script and rehearsed. She is extremely formal and lacks trust and reliance, due to her upbringing.
While her father tolerates Ayano's presence at the school, Megami herself does not and openly confronts her. It is unknown why she is acting this bold. She would use her bare hands when apprehending Ayano, as opposed to pepper spray.
Megami has a charismatic aura of confidence and maturity which sometimes results in adults feeling inferior to her, especially as she talks to adults as if they were her equal, rather than her senior. Given her upbringing, Megami views crying as an activity that is only performed by failures; something not befitting of a member of the Saikou family.
If Ayano is alone and gets close enough to the computer, Megami will begin speaking. It will shut off after she finishes her monologue, and will not turn on ever again, unless the game is restarted.
YandereDev has said that Megami's routine will put her in close proximity to Senpai or other students.
Megami is the heiress to the large business conglomerate Saikou Corp. Most of her life was spent inside of Saikou Corp headquarters, which is also where her family lives.
Megami's childhood was cold, sterile, clinical. Her "CEO training" began around the same time as her formal education. Training and education were the two focuses of every day. She didn't get to spend much time around other children and was influenced to believe that desiring playtime or feeling loneliness were weaknesses, so she voluntarily suppressed her own desire to play or have friends.
Someone attempted to bully her, but Megami won the conflict. 
The rivals have been stated to each have a dark secret.
The topics towards Megami Saikou are Negative/Neutral/Positive as follows:
- Everything else.
- Main article: Kencho Saikou
YandereDev states that her younger brother, Kencho, is the only person who knows how to get under Megami's skin, push her buttons and make her lose her temper. He repeatedly tries to compete with Megami, though she clearly surpasses him.
If Kencho died, Megami would see the death as a "tremendous waste of time and money."
Main Article: Taro Yamada
It is unknown if Megami likes Senpai or not, but it is mostly thought that she does. Megami will try as hard as she can to keep Senpai safe from any harm. If Senpai tries to commit suicide after he sees his sister die, she will run over to try and stop him.
Student Council Members
- Main Article: Student Council
Megami strongly cares about the Student Council members and would go so far as to 'violate her orders' if one of them was harmed. If the player kills one of the student council members, cameras and metal detectors will be set up around the school.
If someone were to openly explain their perverted fantasies involving the Student Council she would show no reaction whatsoever.
- Main Article: Ayano Aishi
Since she knows Ayano's true nature and they are in the same year in the same school, Megami kept a close eye on Ayano.
During her computer monologue, Megami is very hostile to Ayano and will refer to her as a "vulgar creature" and that she would "exterminate" Ayano if she could. This shows that she isn’t very fond of Ayano. YandereAni has stated that in the full game, Megami will not be hostile if the player doesn't make a bad call. It is not yet known what a "bad call" refers to.
- Main Article: Kaga Kusha
Megami thinks Kaga is unpredictable, but a potential cause of slight concern.
- Main Article: Kizana Sunobu
- Megami was inspired by Fujisaki Shiori from Tokimeki Memorial, Juliana Everhart from Valkyria Chronicles 2, and Satsuki Kiryuin from Kill la Kill.
- She is YandereDev's favorite rival.
- Her name Megami means "Goddess" and Saikou means "The Highest/Maximum".
- When the rivals were introduced, Megami's name was initially misspelled as 'Megami Saiko'. This was confirmed to have been an error. 
- She is the richest student at Akademi.
- How Megami judges herself is similar to how Ayano judges herself.
- YandereDev's current reasoning for her absence in the first nine weeks of school is that she was being monitored by a family member, so that she will be prepared to inherit and operate the Saikou business empire. There will be more to it, however, YandereDev would not like to spoil it.
- She will attend classroom 2-2 via webcam until week 10.
- In the January 1st, 2016 Build, the player could move the camera angle while crouching so that the floor didn't show, and it was possible to see Megami under the fountain, sitting down, with a white wall behind her. That white wall appeared black from the north side of the fountain. When Yandere Vision was activated, she had a red outline, signifying that she was dangerous.
- She was subsequently lowered deeper beneath the fountain in the January 2nd, 2016 Build, before being moved to the south side of the school wall, far away and still below the ground in the February 1st, 2016 Build.
- As of the March 15th, 2016 Build, she is located behind the houses that are across from the school gate.
- Megami arrives to school in a helicopter.
- Megami's elimination methods will be the most plot-related.
- In the event of her death, her younger brother would inherit Saikou Corp.
- YandereDev has said that she "will be the end of everything."
- If Megami were given prior knowledge and preparation time for a fight with Osoro Shidesu, Megami would win.
- If a knife throwing ability were to be added to the game, she would be able to catch it in mid-air.
- If Yandere Vision is activated while Megami is monologuing, the speech will be slowed down.
|“||Is someone there?...Ah! It's you...Why have you come here? Have you come here to taunt me? Do you even know who I am? I know who you are. I know WHAT you are. My father won't allow me to attend school while you are..."active". He has a reason for tolerating your presence at this school. I don't. You are a vulgar creature that is only allowed to exist because you serve a purpose. If it was my decision, then every last one of you would be exterminated. Have fun while you can. If you and I ever cross paths...you're going to have a bad time.||”|
— Megami's monologue to Ayano when Ayano is seen by Megami in the Student Council Room.
|“||My top priority is to put a stop to anyone that poses a threat to this school! Senpai! I think someone may be stalking you. But don't worry...I'll keep you safe.||”|
— Megami in "Yandere Simulator Rival Introduction Video" 
|“||I heard rumors about a dangerous person causing trouble at this school. As student council president, it is my duty to find this person and put a stop to them. Senpai, don't be alarmed but I believe that someone may be stalking you. Don't worry. I won't let them harm you. You'll be safe with me. I promise.||”|
— Alternate Megami line for the "Rival Introduction Video".
|“|| I've received several noise complaints from the other clubs. I'm not sure what you're doing here, but whatever it is, you need to do it more quietly.|
Yes, well, whatever you need to calculate, do it at a lower volume.
It would be more preferable if your experiments did not involve explosions whatsoever.
If I continue receiving noise complaints, your club's funding will be reduced until you can't afford anything that combusts.
Your list of enemies will only grow if you continue to disturb the other clubs. I'll be leaving now.
That's exactly the noise that people have been complaining about.
|“||...I appreciate the gesture.||”|
— Hypothetical dialogue of Megami reacting to someone giving her a flower.