If the female clone's actions become more extreme, Naruto would likely become more serious. He has a strong sense of justice and protecting his friends. He wouldn't let her harm anyone. He might try to use his own ninja skills to subdue her and figure out a way to reverse whatever made her this way. He'd also draw on his own experiences of being an outcast and try to reach out to her on an emotional level, hoping to change her yandere ways.
He might be initially confused. Naruto is used to dealing with all kinds of opponents and situations, but a yandere Kyuubi would be a new and strange thing for him. He could try to reason with her at first.
Naruto might be really confused at first. He's used to people being friendly or having normal crushes, but a yandere is a whole different level. He'd probably try to talk to her and understand why she's acting so strangely.
Naruto would probably be really confused at first. He's used to a loving mother figure, not a yandere one. He might try to talk to her and understand why she's acting so strangely.
Naruto might be initially confused. He's used to people being friendly or at least straightforward with their intentions. So when Mikoto starts showing her yandere side, like getting overly possessive, Naruto would probably be like 'What's going on?'. He could try to talk to her and understand her behavior at first.
At first, Naruto might be really confused. He's used to the normal Sakura, so when she starts acting all yandere, he'd be like 'What's going on, Sakura - chan?'. He'd probably try to talk to her and find out what's wrong.
Naruto might also feel a sense of responsibility. He might think that he did something to cause Yugito to act this way. So he could start to limit his own actions to avoid triggering her yandere behavior. For instance, he might stop being so friendly with other girls in front of her. But at the same time, he would not give up his own dreams and values, and would try to make Yugito understand that her behavior is not acceptable in a way that is both firm and kind.
Naruto might be initially confused. He's used to people being friendly, but Yandere Ino's possessiveness would be new to him. He could try to talk to her to understand what's wrong. But if she gets too extreme, he would probably be a bit scared and try to distance himself.
In a more complex scenario, the female clone could be a result of some experiment gone wrong. She has Naruto's memories of his loneliness and uses that as a way to justify her yandere actions. She thinks she is the only one who can truly understand Naruto and wants to keep him in a world where it's just the two of them. She might even try to make Naruto believe that his real friends are against him so that he depends only on her.
Kakashi would be quite impressed by Naruto's creativity in using the clone jutsu in such an unorthodox way. He would also be cautious though, knowing that any new and untested jutsu can have unforeseen consequences. His friends from Team 7 would also start to think about how they could incorporate this new form of Naruto's clone into their battle strategies. For example, they could use the black book clone to gather intelligence or as a decoy in a more complex and unexpected way.
At the start, Ash might underestimate Hunter J's yandere nature. He'd think he could just handle her like any other enemy. But as she starts to show her obsessive side, like targeting his Pikachu specifically or trying to isolate him from his friends, Ash would become more cautious. He would start to analyze her motives and actions more carefully. He might even try to find out if there's a way to cure her of her yandere tendencies, but if that's not possible, he'd be ready to battle her with all his might. His love for his Pokémon and his friends would fuel his determination to stand up to her.