One idea could be Karai dealing with the challenges of hiding her pregnancy while still being involved in the TMNT world. Maybe she has to keep it a secret from the Foot Clan as they might see it as a weakness.
Another plot could be that Karai discovers she's pregnant and initially wants to get rid of it because of her loyalty to the Foot Clan and her role in their battles. But as the pregnancy progresses, she starts to have second thoughts and the story could be about her internal struggle between her old life and this new life growing inside her.
It could be one of the Turtles. For instance, if it's Leonardo, the story could be about how their relationship develops from being enemies to having this very personal connection. Their different ideologies would add a lot of depth to the story as they figure out how to raise a child together.
Perhaps a plot where Leo discovers some new powers or abilities that are related to his pregnancy. It could be something that he has to learn to control quickly. And then there could be a story arc about the team finding a way to ensure a safe delivery for Leo, which might involve seeking out some very rare or magical items.
One idea could be that April and Karai are forced to team up against a common enemy that threatens both their worlds. They start off distrusting each other but as they face challenges, they learn to rely on one another's skills.
It could become more complex as they start to think about the future. They would have to consider how to raise the child within the context of their different backgrounds. Leo, being a turtle and a part of the TMNT family, and Karai, with her own history. This might lead to some disagreements but also deeper conversations about their values and what they want for their family.
Perhaps a plotline could involve the discovery of some sort of prophecy or special power associated with their unborn child. This would draw the attention of both good and bad forces in the TMNT world. They would then have to protect the pregnancy from those who might want to use the baby for their own gain. It could also be about how they grow closer as a couple during this time, learning more about each other and their capabilities as future parents.
Another interesting plot could be that the reader is a time - traveler from the future. They come back to the present day and meet Leo. Leo is initially suspicious but as they work together to prevent a future disaster that the reader knows about, they fall in love. It adds an element of mystery and adventure to the story. Plus, the time - travel aspect can bring in different versions of the TMNT universe and how they interact with the current situation.
Maybe in a different universe where their clans have a more peaceful co - existence. Leonardo and Karai meet during a cultural exchange of sorts between the turtles and the Foot Clan. As they learn about each other's cultures and values, they grow closer.
A possible plot for the leonardo and karai lemon fanfiction could be that there is a prophecy about their union being the key to saving their world. At first, they are reluctant and even hostile towards each other. But as they start to explore the prophecy and what it means, they begin to develop feelings. Along the way, they have to overcome the distrust of their respective groups, and their relationship blossoms as they fight for the greater good.
One possible scenario in a fanfiction about April and Karai could be their relationship evolving from rivalry to an unexpected alliance. They start off as enemies due to their different allegiances in the TMNT 2012 universe. April, being associated with the Turtles, and Karai, with the Foot Clan. However, as they face common threats or discover shared secrets, they might begin to work together. This could lead to some really interesting character development for both of them, as they learn from each other's strengths and weaknesses.
Karai's sad story in TMNT Legends might involve her complex relationship with the Foot Clan. She was often caught between her loyalty to the Clan and her own sense of right and wrong. Her father, the Shredder, was a cruel and controlling figure, which must have been difficult for her to deal with.