A theme of rediscovery could be present. Naruto discovers more about Kushina as he grows older, and through this rediscovery, his love for her deepens. Also, the theme of hope. Kushina's love gives Naruto hope in difficult times, and a fanfiction could expand on how this hope shapes his character and his journey.
One theme could be sacrifice. Kushina sacrificed herself for Naruto, and a fanfiction could explore how Naruto honors that sacrifice through his love for her. It could also be about legacy, as Naruto carries on Kushina's will.
Family love is a major theme. Even though Naruto didn't get to grow up with Kushina, the love between them is strong. A fanfiction could show how they overcome the time apart and build a strong family - like bond. Another theme could be protection. Naruto would do anything to protect his mother's memory, and Kushina would have done the same for him.
Well, the plot could start with Naruto being turned into a vampire in some sort of accident or dark magic. Kushina, being the strong - willed woman she is, is initially repulsed but then gradually sees the good in Naruto even as a vampire. Their love could develop as they face challenges together, like fighting against those who want to harm Naruto because of his new vampire nature.
Well, a frequent theme is the exploration of Naruto's new - found godlike abilities in relation to his love for Kushina. It could be that his powers are somehow connected to his feelings for her. Another common aspect is the emotional healing that comes from their relationship. Naruto may have had a tough life, and his connection with Kushina in these fanfictions can be a source of comfort and growth. Additionally, there might be themes of heroism, where Naruto, with his godlike powers, is seen as a hero in Kushina's eyes and vice versa.
Often, there's a theme of discovery. Maybe Naruto Uchiha discovers something special about Kushina Uzumaki that draws him to her, like her strong will or her unique Uzumaki abilities. And also, redemption can be a theme. If Naruto Uchiha has a troubled past, Kushina's love could be the thing that redeems him. There's also the theme of family, as Kushina is Naruto's mother in the original story, so in these fanfictions, they might create a new family dynamic with their relationship.
One common theme is sacrifice. Kushina sacrificed herself for Naruto, and fanfics often explore this aspect deeper, showing how her love was so strong that she was willing to give up her life. Another theme is the unbreakable bond. Even though they didn't have much time together in the original story, fanfics expand on the idea that their love and connection are eternal.
In Naruto - Kushina fanfiction, the theme of connection is quite prevalent. This connection can be on a physical level, like Naruto inheriting Kushina's strong chakra, or on an emotional level, such as Naruto feeling an unbreakable bond with his mother even though she's gone. Another common theme is redemption. Maybe there are elements in Kushina's past that need to be redeemed, or Naruto uses the knowledge of his mother's past to redeem himself or others. And finally, the theme of growth is often seen. Naruto grows as a person and as a shinobi by learning about Kushina, her struggles, and her triumphs.
It could also be related to some hidden family secrets or prophecies. Maybe there was a prophecy that Naruto would bring great destruction in the future and Kushina, believing in it, thought she had to stop him before it was too late. This would be a very complex and heart - wrenching betrayal if it was based on such a false premonition.
One possible reason could be some sort of dark influence or curse that makes her lose her maternal instincts. Maybe a powerful enemy targets her and in order to protect Naruto from further danger related to her, she feels forced to abandon him. Another reason might be that she is made to believe false information about Naruto, such as that he will bring great disaster to the village in the future.
One possible reason could be a mission. In many Naruto - related stories, missions often take characters away from their families. Naruto might have received a highly important and dangerous mission that requires him to be away from Kushina for a long time.
He could learn powerful sealing techniques. Kushina was known for her sealing skills, and she could pass them on to Naruto. This would give Naruto an advantage in battles and also in containing the Nine - Tails' power.
It could also be due to some external influence. Perhaps an enemy used some kind of mind - control or manipulation on Kushina. They made her think that Naruto was a threat, so she decided to disown him. In the Naruto universe, there are many powerful villains who could potentially do this kind of thing.