Rivals are the main antagonists of Yandere Simulator. In the future there will be ten rivals for the ten weeks of Story Mode, with one rival appearing each week. They have not been fully implemented yet, but they have been introduced in a video.
They are the most important people to eliminate, as they all have a crush on Senpai (with the exception of Senpai's sister). If the rival is not eliminated by the end of their week, they will confess their love to Senpai (or make him promise to never have a significant other, in the case of Senpai's sister) under the Confession Tree behind the school on Friday, and the player will get a Game Over. A girl confessing to a boy underneath a cherry tree is a cliché in anime and will be drawn upon in the game. Each rival in the game is an anime archetype, inspired by popular concepts and stereotypes. However, not all of them will be based on a "dere" archetype.
In the current debug build, there are no actual NPCs who function like proper rivals, so there is no way to win the game yet. In the full game, they will not be in the school until their week comes. Each rival will be introduced via a cut-scene conversation with Info-chan. The rivals from weeks two to ten will each have a reason for not coming to the school for the previous weeks of the game. They will also have a short cut-scene that shows how they met Senpai and why they are attracted to him. Some of the cut-scenes will be humorous to balance out the other dark elements of the game.
Senpai will not fall in love with girls of his own accord. He will start to develop a crush on a rival if she has five interaction events with him. There will be one "event" with Senpai each day, with the final event being a love confession. It is possible for Yandere-chan to sabotage each event.
Even though the main object of their desire is Senpai, all rivals will have a secondary crush on another male student. This allows the main character to matchmake every rival with their suitor as a way of eliminating them. If the player chooses to make Senpai female, then Yandere-chan and Senpai will be lesbians and all of the rivals will be bisexual.
Every rival wears special stockings to make themselves stand out and will have unique panties that suit their personality. In the future, rival hairstyles and accessories might be unlocked after beating the game once.YandereDev has considered the idea of allowing the player to dress up as any of the rivals after eliminating them.
As the game progresses, each rival is more difficult to defeat than the previous one, sometimes because of popularity.
Rivals are seen outlined in red in Yandere Vision, although this outline might have other identifications, as traumatized students also have a red aura.
The rivals will be able to realize that the player is stalking them, and react accordingly.
However, they will never know that they have competition for Senpai.
This section contains spoilers.You have been warned!
NOTE: These rivals are only for testing and are unlikely to be rivals in the final game. Currently, there have only been three test rivals.
Kokona Haruka is the current test rival. Although she will not be an actual rival in the final game, she is being used to test elimination methods. As shown above, she has a crush on Senpai, so Yandere-chan has a reason to eliminate her - however, eliminating her will not win the game. The player will still lose at the end of the week since she is not programmed as an "official rival".
Story Mode Rivals
This section contains spoilers.You have been warned!
All rivals have been planned out with official rival designs since February 2016. Back in late November 2015, an artist had created full-body illustrations for every rival character. YandereDev asked for a few modifications, and then promised that he would officially reveal all of them in his upcoming Rival Introduction Video. Only Megami Saikou currently exists in the game, as seen in the laptop of the Student Council Room.
As of 28th of September, 2016, the rivals have been revealed in the Rival Introduction Video.
Osana Najimi will be the first rival in the full game. NOTE: The character who stands under a cherry tree is "Rival-chan". Osana will be a completely different character.
Her AI is currently incomplete, and she has not yet been implemented into the game, so she cannot be interacted with. Furthermore, YandereDev needs dozens of male and female animations before he can add in Osana. Because of this, the player cannot beat the game, and will always get a game over on Friday at 6:00 PM due to Osana confessing her love to Senpai.
She was originally shown in the first intro to be Senpai's childhood friend and a tsundere. In the second intro, her tsundere tendencies and her background as Senpai's childhood best friend are not mentioned in the slightest. However, YandereDev says that her character concept has not changed.
YandereDev has also mentioned that Osana will essentially function as a tutorial rival.
Oka Ruto, the president of the Occult Club, will be the fourth rival in the full game, although she does not currently function as one. She is considered a cross between the Hex Maniac from Pokemon: X and Y, Tharja from Fire Emblem: Awakening, and Tomoko from WataMote.
Muja Kina, the substitute nurse, will be the sixth rival. Her character trait is unintentional sexual innuendos. She is pure and innocent.Nasu Kankoshi will be on vacation during her week as a rival. She will disappear from the school after her week is over, even if she is eliminated peacefully.
Mida Rana, the substitute teacher, will be the seventh rival. The teacher's trait is intentional sexual innuendos, and she will be sultry and seductive. She can be called upon by a Teacher's Pet if they discover a corpse or witness a murder. Yandere-chan will be able to matchmake her with a student. She will disappear from the school after her week is over, even if she is eliminated peacefully.
Osoro Shidesu, the leader of the delinquents, will be the eighth rival. Although she will not be evil, it is known that she has been suspended from school for something gravely serious. Not only that, but she is the strongest and most dangerous girl in school.
She is the leader of a gang, and she always has her cronies nearby.
Hanako Yamada, Senpai's sister, will be the ninth rival in the full game. Her appearance has been updated as of November 28th, 2015. She does not lust sexually after her brother, but she loves him so much that she does not want him to get a girlfriend, as she wants all of his attention. She is said to be one year younger than Senpai and two school years behind him.
Megami Saikou, the student council president, is the tenth rival in the full game. She will be a lot like Nayuta from Yumina the Ethereal VN. She will also be a strict disciplinarian. She will be a complete Mary Sue, and the most popular girl in school.
Like Story Mode, there will be ten rivals, with one appearing each week. They will be created out of pre-existing assets instead of original designs.
The rivals in 1980s Mode will have a crush on Yandere-chan's father. This is because the player character of that mode will be the yandere from the Mysterious and Basement Tapes, who is Yandere-chan's mother. Yandere-chan's father is also Yandere-chan's mother's senpai.
She is the only known rival at the moment. However, she might be killed in the intro animation of the mode, instead of her elimination being left up to the player to avoid a paradox.
Endless Mode Rivals
In Endless Mode, the game will randomly generate a rival each week for an unlimited number of weeks until Yandere-chan gets caught. The player will have to stalk Senpai until they identify the newest rival. They will not have special stockings. They will have the normal functions of a rival, and the player will be able to eliminate them the same way as any rival in Story Mode.
Possible DLC Rivals
YandereDev has stated that he might consider creating DLC rivals in 2014. These rivals would either be non-canon, or would require unique coding to be implemented. If DLC rivals do get added to the game, they would most likely appear after Megami's week.
According to YandereDev in 2017, he's still considering this idea, including Kokona as a DLC rival.
There will be 15 elimination methods that will work on all 10 rivals. Each rival will also have one unique elimination method that is restricted to only them. In fact, it is possible that in the full game some methods will be tied to scripted events which only involve the rival. The rivals were built around their elimination methods.
Once a rival has been eliminated non-lethally, they become a regular NPC and all "normal NPC interactions" become available to them.
The player will not be able to threaten or intimidate rivals, only directly eliminate them one way or another. Blackmail will not be available either because the game is about taking direct action against Yandere-chan's rivals.
At one point, there was an elimination method that was similar to tampering with the school diving boards so that the rival would smash their face into the ground, but it was criticized for being "too Looney Tunes".
In the future, killing a rival early will give the player the option to skip forward to the next week, or play through the current week.
There is an old post detailing all ten of the rivals. Although outdated, some information has persisted and remained in the game's plan, such as Osana Najimi and Mida Rana.
There is a page that shows most likely outdated designs of a few of the rivals. The artist mentions that they are subject to heavy change, as well. YandereDev linked to the page in older comments on here.
A car bomb would be an appropriate way to eliminate one particular rival, but this is not very yandere-like.
Certain rivals may be capable of self-defense, but Osana Najimi will not be one of these, since she is a "tutorial" rival. Some rivals are the type of people who would be able to catch a knife if it was thrown at them, even if their back was turned. The Substitute Nurse and Substitute Teacher, however, are not.
Only two rivals will ever directly confront Yandere-chan, and they, including a third rival who can defend herself, will fight in manners completely different from one another.
Koharu Hinata had a crush on Senpai in the September 18th, 2015 Build, and was, therefore, a rival. This mistake was changed with the October 8th, 2015 Update.
All of the rivals will be on good terms with Senpai. If he sees them covered in blood, he will not assume they committed a crime. If one of the rivals is arrested, Senpai will be in disbelief, but he will have no way to overturn the evidence against her and will be powerless to help her.
It will be impossible to get rid of one rival to instantly cause the elimination of another.
Each rival's birthday will fall on a different month of the year.
YandereDev later revealed that he only used those names because he thought they were common, generic Japanese names.
YandereDev also revealed he wants names that reference who the character is. For example, Senpai's childhood friend is named Osana Najimi because osananajimi (幼なじみ) means "childhood friend" in Japanese.
There was originally going to be a short loli rival, but YandereDev is opposed to the idea now because of all the work and problems it would create.
If the rivals were in Hogwarts, most of them would be Gryffindor.
Only rivals will have dark secrets, not regular NPCs, with the exception of certain characters like The Journalist.
Pregnancy is a possible dark secret of one of the rivals.
If the rivals have siblings, they do not attend Akademi High School. The only exception to this rule is Hanako Yamada.
Some of the rivals are intended to be likable people who do not deserve to die, possibly making the player feel some guilt for whatever they do to them.
YandereDev's current plan as of January 14th, 2016 does not include a rival who Info-chan will refuse to help kill or torture.
Implementing the ability to disguise Yandere-chan as a rival is very tricky, so it cannot be guaranteed.
YandereDev is considering the old idea of taking trophies from rivals, but it is low priority.
YandereDev likes the idea of breaking into a rival's home and smashing her possessions, but this would only happen if a small town is added.
Killing a rival who is also a club leader will not shut down the club; each club that contains a rival in it will have one more person in it than usual so that it can stay open even though someone died. A substitute will take the place of the normal club leader.
Each rival's personality will be demonstrated through unique animations that other NPCs do not possess. Similarly, they will also react to the player's presence in ways that other NPCs do not.
In one or two cases the player will be able to use a former rival as a "tool" to help eliminate a future rival. However, this won't be the case with all rivals.
Befriending a rival may supply Yandere-chan with a permanent reputation gain of +1, per befriended rival.
A befriended, former rival may comment on Yandere-chan not interacting with Senpai.
Although most rivals travel to school through walking or taking a train into town, Megami will arrive by helicopter.
YandereDev is considering having a rival's ghost appear where they were killed.
Some of the rivals inherited their interests from their parents.