Well, perhaps the fanfic could start with Mai realizing she's pregnant. Zuko is overjoyed but also a bit scared. They start making changes in their living situation. Zuko may focus on making the Fire Nation a better place for their child to grow up in. Mai, on the other hand, could be dealing with her own insecurities about motherhood. Their relationship might also face some strain as they adjust to the new situation.
One possible plot could be that Zuko and Mai are initially shocked by the pregnancy. They then start to prepare for the baby's arrival. Zuko might be a bit overprotective, while Mai tries to keep her cool. Their friends could be excited or worried, and there could be challenges like dealing with the public's reaction as they are important figures. Maybe they face some threats to the unborn child which they have to overcome together.
Zuko's personality could be shown as more tender and caring than ever. He might be constantly worried about Mai's well - being and that of the baby. His sense of responsibility would be heightened. Mai, on the other hand, while still maintaining her dry sense of humor, would show a more vulnerable side. She may not be as openly emotional as Zuko but her actions, like making sure the nursery is safe, would show her love and care for the unborn child.
One plot idea could be that they initially struggle with the news. Zuko might be worried about how his role as a leader would be affected while Mai is dealing with the physical and emotional changes. They could face challenges from the Fire Nation's traditional views on pregnancy and family. Another idea is that they go on a journey to find a safe place for their child to be born, away from the political unrest in the Fire Nation.
Maybe a plot where Mai is kidnapped by enemies of the Fire Nation who want to use her to get to Zuko. Zuko then embarks on a dangerous rescue mission. Along the way, he realizes just how much Mai means to him. Or a story where Zuko and Mai are forced into an arranged marriage by Fire Nation politics. At first, they resist, but as they spend more time together, they start to develop real feelings for each other that go beyond the political arrangement.
In a 'zuko gets oc pregnant fanfic', the plot could center around the OC being from a different background than Zuko. Their relationship was a bit of a forbidden love to start with. When she gets pregnant, Zuko has to make a choice between his loyalty to his family or kingdom and his love for the OC and their unborn child. It could also involve the OC trying to fit into Zuko's world while dealing with the physical and emotional changes of pregnancy.
In the fanfiction, it could be that Jin discovers she's pregnant during a time of unrest in their land. Zuko and Jin then have to find a way to keep the pregnancy a secret from their enemies. As the story progresses, they might find unexpected allies who help them. Zuko could also be training to become a better fighter to protect his family, while Jin focuses on taking care of herself during the pregnancy. This could lead to a lot of character development for both of them.
Well, perhaps the plot could start with an unexpected encounter between Zuko and Toph that leads to a deepening of their relationship. Then, when they find out about the pregnancy, they struggle with their own insecurities. Zuko might be worried about being a good father like his own father was a terrible example. Toph, on the other hand, might be concerned about how her blindness will affect her ability to care for the baby. But together, they start to prepare for the new life, learning about parenting and also facing any threats or opposition from those who don't approve of their relationship.
One plotline could be the challenges they face in the Fire Nation. Since Zuko is the Fire Lord, there might be political implications of his partner being pregnant. People might try to use the situation to their advantage or there could be concerns about the safety of the unborn child.
A plot twist could be that an enemy from their past resurfaces because they hear about the pregnancy. This enemy wants to use the unborn baby for some malicious purpose, perhaps as a bargaining chip or to gain some sort of power. Naru and Mai then have to go into hiding and protect themselves and the unborn child while also trying to figure out the enemy's motives and how to stop them.
Perhaps the fanfiction delves into the baby's unique abilities or characteristics. Since Zuko has a connection to the Fire Nation and Mai is a skilled fighter, the baby could inherit some extraordinary powers. It could show how they train the baby to control these powers while also giving it a normal childhood.
Zuko can be developed by exploring his role as a leader within the context of his marriage. He may struggle to balance his duties as Fire Lord with his time for Mai. This internal conflict can show his character's depth. He could also develop new bending techniques influenced by his love for Mai. As for Mai, she can develop by getting involved in more political matters, standing by Zuko's side and using her intelligence to influence decisions. She could also start to make more friends in the palace, which would change her somewhat solitary nature.