They might be original characters created by the fanfiction writer. In this case, the writer would have the freedom to define their personalities, backstories, and how they met. Maybe Milo is a kind - hearted and adventurous guy and Kida is a strong - willed and intelligent woman, and their relationship is the starting point for the pregnancy story.
The plot could involve Milo and Kida preparing for the arrival of their baby. They could be seen shopping for baby clothes, setting up the nursery. And they might also have some cute moments like feeling the baby's kicks together and sharing their hopes and dreams for the child.
In many Milo and Kida kiss fanfictions, the 'Forbidden Love' trope is quite common. Maybe their different backgrounds or social standings make their relationship difficult. Their kiss then becomes a symbol of defying the odds. Also, the 'Love - Confession - Through - Kiss' trope is popular. Instead of using words, they express their deep love for each other with a kiss. It can be a very powerful and emotional moment in the fanfiction.
Writers can create tension by having Milo and Kida have an argument or a misunderstanding before the kiss. This makes the moment of the kiss more anticipated as the readers wonder if they will be able to resolve their differences. Another way is through physical proximity. If they are constantly in close quarters but not yet kissing, it builds up the tension.
In a more creative take, it could be an unknown character from a far - off land who visited Atlantis. Kida could have fallen in love with this mysterious stranger during his brief stay, and he is the father. This would open up the story to explore different cultures and how they interact with Atlantis.
Maybe in the fanfiction, Kida's pregnancy is a sign of hope for Atlantis. The people see it as a new beginning and start to make plans for the future. However, there are some who are jealous or afraid of the power the baby might bring. Kida then has to face these challenges while also taking care of herself during the pregnancy.
Another way is to focus on the relationship between Kida and those around her. Her family and friends might have different reactions to her pregnancy with the crystal. Some could be supportive, while others might be skeptical or even hostile. This would create interesting character dynamics.
One possible story could be that the crystal has some sort of magical origin. Maybe it was a gift from the gods of Atlantis. Kida, being pregnant with it, could have strange dreams and premonitions. The crystal might start to influence her in ways she doesn't understand at first. For example, it could give her the ability to communicate with the ancient spirits of Atlantis more clearly, and through her pregnancy, she is meant to bring about a new era of understanding between the past and the present of Atlantis.
Authors can make Kida's hurt more believable by describing her physical reactions. For example, if she's been injured, they can write about her wincing in pain or having difficulty moving.
There are some great Milo x Melissa fanfictions out there. One popular one focuses on their adventures together outside of the normal chaos in their town. It shows their friendship evolving into something more special as they face challenges side by side.