Another theme could be self - discovery. The characters might be on a journey to discover more about themselves, and their relationship helps in this process. For example, Aki might learn something new about herself through her interactions with Grey, and vice versa.
One common theme is the exploration of their relationship development. It could start from their initial meeting and gradually show how they grow closer.
Another theme is growth. As the story progresses, both Shima and Aki may grow as characters. For example, they could learn important life lessons from their interactions with each other. In some fanfictions, they overcome personal weaknesses with the help of their relationship.
One common theme is friendship evolving into love. Since they start as friends in the original story, fanfictions often explore how that friendship deepens into a romantic relationship over time.
A common theme is the clash of two different worlds. Naruto's world of ninjas and the grey lady's world, whatever it may be in the fic, often collide. Another theme could be the power of friendship. Despite their differences, they form a bond.
One common theme is discovery. The oc often discovers Jean Grey's powers and her complex personality. For example, in many stories, the oc is new to the X - Men world and has to learn about Jean Grey. Another theme is friendship. They start as friends and sometimes it develops into something more. In some fanfictions, they support each other through tough times like when Jean Grey struggles with the Phoenix Force.
One common theme is the power dynamic. Naruto has his own set of powerful ninja abilities and Jean Grey has her telepathic and telekinetic powers. So, stories often explore how they use their powers together or in contrast to each other.
One common theme might be adventure. Since they are two characters (presumably from some fictional world), their stories could involve going on exciting quests together. Another could be friendship, as they might develop a deep bond through their shared experiences.
Well, one of the common themes is the celebration of love and new life. It's not just about the pregnancy, but also about the love that Grey and Femnatsu share that led to this new addition. There could be themes of sacrifice too. For instance, they might have to sacrifice some of their personal adventures or time for themselves to focus on the pregnancy. And then there's the theme of unity. They have to be united in their decisions and support for each other throughout the pregnancy journey.
A very popular theme is loyalty. In many fanfictions, Bella and Taha Aki are extremely loyal to one another, standing by each other through tough times. Also, the theme of growth is quite common. They grow as individuals and as a pair, learning from their experiences and becoming better versions of themselves. For example, they might face a difficult situation like a natural disaster in the story world and in the process of surviving it, they grow and change.
Often, there are themes of emotional connection between Yusei and Aki. The fanfiction might explore how they support each other through difficult times, and then build on that with the 'lemon' aspect which adds a layer of physical and sexual tension. Another theme could be the growth of their characters within the relationship, as they face challenges together and become closer both emotionally and physically.