Well, it could explore themes like responsibility. With a pregnancy, both MrIncredible and Mirage would have to think about their roles not just as superheroes or villains in Mirage's case, but also as future parents. It could also touch on themes of acceptance, especially if their relationship was not in a very stable state before the pregnancy. There could be a theme of sacrifice as well, as they might have to give up certain aspects of their previous lives to make room for the new family member.
I'm not sure there are a lot of such fanfictions. However, this is a rather unusual and not-so-common concept for a fanfiction. It might be difficult to find mainstream ones. Maybe you can try searching on some specialized fanfiction websites and use very specific search terms to see if there are any that match.
The theme of sacrifice could be present. Sesshomaru might have to sacrifice his solitary lifestyle and some of his pride to be there for Kagome and the baby. Kagome may have to sacrifice her own plans and dreams for a while to focus on the pregnancy. Additionally, the theme of unity could be explored as they have to be united in facing the challenges that come with her pregnancy, such as potential threats from other characters who don't approve of their relationship.
A theme could be about the reactions of their friends and family. For example, how Bakugou's explosive personality might handle the situation and how Uraraka's more gentle nature might influence their approach. Also, it could be about how the pregnancy changes their relationship dynamics, like growing closer or having some initial conflicts due to the new situation.
Common themes in 'Apex Legends Wraith x Mirage fanfiction' include the exploration of their individual in - game backstories. Writers often use their pasts to create a connection between them. Also, the theme of mutual respect is prevalent. They learn to respect each other's strengths and weaknesses. For instance, in many fanfictions, Mirage's showmanship and Wraith's stealthiness are both respected and they find ways to combine these qualities. And of course, there's the theme of a budding romance in some of the fanfictions, which adds an extra layer of intrigue to their relationship.
One common theme is the struggle between their normal lives and their extraordinary abilities while in a relationship. Another could be the idea of secrecy, as both might have to keep parts of their lives hidden from each other initially. And of course, the classic theme of falling in love against all odds.
Another theme could be the loss of innocence. At 15, a girl is still a child in many ways, and pregnancy can suddenly thrust her into a very adult situation. This could be explored in terms of how she copes with the loss of her carefree youth.
Adventure is also a popular theme. Writers often take the two characters on exciting quests or missions. This allows for a lot of action - packed scenes and the development of their relationship in the face of danger.
One possible theme could be about the challenges and joys of impending motherhood. Another could be how the character's relationships change with her partner and those around her during the pregnancy.
One possible theme could be about new life and the responsibilities that come with it. Even though Mewtwo is a powerful Pokémon, dealing with pregnancy might bring out a different, more nurturing side of it.
One possible theme could be the challenges they face as a couple during the pregnancy. Another could be the anticipation and excitement of starting a family.