These characters are the most important people to Yandere Simulator's plot. Some of the main characters are not implemented yet.
- Main Article: Yandere-chan
- Main Article: Senpai
Senpai is the love interest of Yandere-chan and her obsession.
If Yandere-chan can successfully eliminate all rivals in the game, then she will be able to confess her feelings to Senpai.
If the player fails to eliminate Yandere-chan's current rival that week, the rival will confess her feelings, and Senpai will accept, leaving Yandere-chan heartbroken.
- Main Article: Info-chan
Info-chan is one of the key characters in Yandere Simulator, being Yandere-chan's main source of help and information. Some males, and even females, pay her lots of money for panty shots.
The player can send her a picture of a person's face to get information about them. This feature doesn't currently work on anyone with an incomplete AI. By sending her panty shots of other students, Yandere-chan can ask for Panty Shot Favors from her as well.
- Main Article: Ryoba Aishi
The mother of Yandere-chan, who is a yandere and will be the protagonist of 1980s Mode. She will not appear in Story Mode for 10 weeks, as she is hunting down The Journalist. The Basement Tapes explain more of her backstory.
- Main Article: Yandere-chan's Father
- Main Article: Rivals
Every week during the 10 weeks in the game, a new female student will fall in love with Senpai and become Yandere-chan's rival. It is Yandere-chan's goal to eliminate the rival before Friday of each current week. There will be one rival per week.
If she fails to do so, her rival will confess her love to Senpai and Yandere-chan will be left heartbroken. Hanako Yamada won't confess her love, rather she will make her brother promise not to get a girlfriend.
Rivals have not been fully implemented yet, but when they are, the first girl planned to rival for Senpai's affections is Osana Najimi.