A different concept could be that a yandere curse is placed on Naruto, and as a result, any girl who gets close to him starts to develop yandere traits towards him. This could lead to a really chaotic harem situation where the girls are constantly fighting over Naruto, and Naruto has to figure out how to break the curse while dealing with their over - the - top affections.
Maybe a powerful and mysterious force affects the minds of some RWBY characters, turning them into yanderes for a particular character. This could lead to a lot of drama as they try to keep their yandere tendencies hidden while also vying for the object of their affection. For example, Ruby could be affected and her normally innocent nature takes on a more possessive and obsessive side when it comes to the person she loves.
Another interesting concept is a yandere fanfic set in an alternate universe. In this universe, the yandere trait is more common among the shipgirls. A particular shipgirl falls for a new recruit and her yandere behavior causes chaos within the fleet as she tries to keep the recruit all to herself, going against the fleet's rules and regulations. This could lead to a lot of drama and conflict as the other shipgirls and the commanders try to deal with her.
One idea could be that the main character, a new ninja in the village, accidentally uses a jutsu that makes all the kunoichi attracted to him. They then start to compete for his attention in various ways, like through ninja skills competitions or by cooking him their best meals.
One idea could be that Yugao is a skilled ninja who is being courted by various male characters in the Naruto universe. Each character brings a different aspect of the ninja world to the relationship, like Naruto with his determination, Sasuke with his mystery, and Shikamaru with his intelligence.
Another plot could involve Naruto accidentally getting involved in a magic or curse situation that binds him with the female characters related to Kurenai. As a result, they have to stay close to him to figure out how to break the spell. During this time, they discover new sides of Naruto and feelings start to develop among them all.
One idea could be that Naruto, with his unique charm and ninja skills, attracts a group of female characters from different villages. For example, Hinata could be part of the harem, still being shy but deeply in love with Naruto. Sakura might also be there, having finally realized Naruto's true worth. And then add some new female characters from other lands, each with their own special abilities and personalities, and they all come together because of Naruto's heroic deeds and kind heart.
One idea could be that Naruto, in an alternate universe, is a powerful leader and Konan along with other female characters from the Naruto world are drawn to his leadership and kind heart. They form a sort of harem around him, and together they face new threats to the ninja world that require their combined skills and powers.
Perhaps the story could be about a ninja who inherits a powerful doujutsu that has some sort of connection to the female characters in Naruto. As he tries to master this doujutsu, these female characters are drawn to him. They end up training together, and during their training, they discover secrets about the doujutsu and their own pasts. This could lead to a series of exciting adventures and the development of deep relationships among them.
One idea could be that Sakura's yandere tendencies lead her to try and isolate Naruto from his other friends. She might start by spreading rumors about them to Naruto, causing some initial confusion and rifts in his relationships.
One idea could be that Tenten becomes yandere for Naruto after he saves her life in a battle. She then starts to secretly eliminate any girl she sees as a threat to her 'relationship' with Naruto. For example, she might try to sabotage Hinata's attempts to talk to Naruto.