Raibaru Fumetsu

This girl is planned as first rival for Senpai's affections, she is also Senpai's childhood friend.

Since her AI is incomplete, Osana Najimi cannot be interacted with (killing, talking, etc.). Yet, she'll still confess her feelings to Senpai on Friday, resulting in the "Heartbroken" ending.

Appearance
Osana Najimi wears the default school uniform, as well as white kogal-style leg-warmers. Osana Najimi wears her orange hair in pigtails with pink and white polka-dotted scrunchies. Her eyes are also orange, and she is the shortest character in the game.

Scenes
In the now out of date intro to the game when you run into Senpai, she can be seen talking to Senpai and acting in a Tsundere manner towards him.

You can see the old intro on YandereDev's YouTube channel.

She also appears in the spinoff game Yandere clicker. Her face was used for the "Imouto" option, described as "A kawaii Imouto who will stab senpai for you." However, she is not Senpai's little sister and should not be mistaken as such.

In Yandere Simulator April 3 update, the Photographs folder had a lot of pictures of her in different positions.

In the newest update, when you press the space bar she now has different animations.

Relationships
Senpai: She is his childhood friend, and has a crush on him. Info-Chan has stated that if she confesses to him, he won't be able to turn reject her. She plans to confess to him under the cherry blossom behind the school at the end of the week (Friday).

Yandere-Chan: Yandere-Chan feels rage that Osana would dare try to take her Senpai away from her. She will be heartbroken if Osana manages to confess to Senpai and the two begin a relationship.

Trivia

 * Silmarly with Kokona Haruka, because she likes Senpai and is a rival, she is mostly hated by the Yandere Simulator Fandom.