Naruko in this fanfiction is most likely a character that the author has developed for the story. It might be inspired by other characters in the genre or it could be a completely new concept. Maybe she has certain unique abilities or traits that make her the target of being double teamed. For example, if it's in a fantasy setting, she could possess a powerful magic that others want to suppress by ganging up on her.
Naruko might also gain some vampire - like powers. For example, she could have increased speed and strength. However, she would also have to face the negative aspects. Vampires are often hunted or feared in many fanfictions. So she would have to constantly be on the lookout for those who would do her harm, and she would have to learn how to control her new vampire nature so as not to attract unwanted attention.
There's also the possibility of pairing Naruko with Sirzechs. His powerful and noble nature could contrast well with Naruko's more brash and energetic personality. It could lead to a story where they have to work together to solve a major problem in the DxD world, and in the process, develop a deep connection.
Her friends are likely to be part of it. A close female friend could be like a pregnancy buddy, sharing her own experiences if she has any. There might also be a mentor - like figure, an older woman who has been through pregnancy and can give Naruko valuable advice on everything from childbirth to raising a child.
Kakashi could also be a character in 'naruto and naruko harem fanfiction'. He can be the mentor figure, guiding Naruto and Naruko through different situations. His wisdom can influence how the harem relationships develop, for example, by giving Naruto advice on how to handle multiple relationships in a proper way.
In this fanfiction, Naruto and Naruko's characters can be developed through their shared experiences. They could face discrimination or special treatment because they are twins. Naruto, who is used to being an outcast, might handle it one way, while Naruko could have a different reaction. This would lead to them growing as individuals and as a pair. They could also develop by learning from each other's mistakes. For instance, if Naruto rushes into a fight, Naruko could teach him the value of planning, and Naruto could show her the importance of believing in oneself no matter what.
Sasuke is often paired with Naruko in these fanfictions. Their relationship can be explored in different ways, like they might start as rivals in this alternate universe too, but their bond develops into something more romantic or a deeper friendship. Another common pairing is with Kakashi. He could be her mentor in a more intense and personal way, guiding her not just in ninja skills but also in understanding the complex politics of the ninja world.
I'm not entirely sure if there is a specific 'Naruko pregnant fanfic'. There are so many fanfics out there that it's hard to say for certain without doing a detailed search. Some fanfics focus on character development, relationships, and unique scenarios, and a pregnancy could be part of such a story. It could explore how the character of Naruko deals with the situation, her relationships with other characters during pregnancy, and so on. But again, it depends on whether someone has actually written such a fanfic.
The pregnancy can be a catalyst for their relationship to deepen. They might start to communicate more openly about their feelings and fears. For example, Sasuke could share his insecurities about being a father, which he has never done before, and Naruko could comfort him.
Naruko might adapt by using her modern - day knowledge of ninja techniques. For example, if she has learned some advanced jutsu in her original time, she can use that knowledge to her advantage in the past. She could also adapt by quickly learning the social norms and customs of the past. If she's from a more modern and liberal era, she might have to adjust to a more traditional and conservative past environment.