For Mason, you can give him some flaws. Maybe he's a bit of a procrastinator at first, not really taking the pregnancy seriously. But as he sees Alex's determination, he changes. Alex could be developed as a very independent character. However, the pregnancy makes her realize she needs to rely on others sometimes. You can show this through her interactions with her friends and family.
It could be that Mason and Alex are in a long - distance relationship. When Alex discovers she's pregnant, it throws their relationship into chaos. Mason has to decide whether to move closer to Alex or try to support her from afar. There could be a lot of drama as they try to make decisions about the pregnancy and their relationship.
Their relationship might become more intimate as they share this life - changing experience. They'll be more reliant on each other for emotional support.
The victim of the kidnapping could be a central character. Maybe it's a journalist who was about to expose a big story and Alex and Mason were hired to stop them, but as the story progresses, the journalist reveals the truth behind the people who hired Alex and Mason.
The relationship could also develop in a more platonic way. They could be like sisters, supporting each other during doctor's appointments and prenatal classes. They might have arguments along the way, but always come back to support each other because they know how tough pregnancy can be.
One possible plot twist could be that it was an unexpected pregnancy. Maybe they were just starting their relationship and this news completely changes their plans. They might have to deal with reactions from their families and friends, some of whom could be very supportive while others might be shocked or disapproving.
The main characters are clearly Alex and Mason, who are presumably in a relationship and have become parents. And of course, their baby is also an important part of the story, though being a baby, it might be more of a catalyst for the growth and development of Alex and Mason's characters.
In fanfiction, Claire can develop from being a bit of a hot - headed rebel into a more strategic hunter. For example, she might learn from her mistakes on hunts and start thinking things through more carefully. Alex, on the other hand, could develop her medical skills further within the hunting context. Maybe she starts using her knowledge to create new ways to treat hunters who get injured on the job.
Supergirl might develop by learning to rely more on Alex's human - based skills and wisdom. For example, in a situation where her powers are nullified, she has to depend on Alex's combat training. Alex, on the other hand, could develop by becoming more confident in her role as Supergirl's support system.
Adventure is also often seen. They might go on quests or explore new places together, which makes for exciting reading. For example, in some stories they are in a jungle exploring ancient ruins. This not only tests their physical strength but also their relationship. Another common theme is self - discovery. As they go through different situations, they learn more about themselves and each other.
Well, they might be into fanfiction about their favorite TV shows. For instance, if they are fans of 'Stranger Things', they could love the fan - made stories that expand on the show's universe.