Perhaps in the fanfic, they don't plan to have a baby at all. It could be a result of some magic gone wrong. A spell that was meant for something else ends up creating a situation where Raven is pregnant with Beast Boy's child. At first, they're both shocked and a bit scared. But then they start to see it as a new adventure. They start to learn about parenting from their own experiences growing up. And as the baby is born, they realize that this new addition to their family has brought them closer together and made them better heroes.
A plot could involve an unexpected pregnancy. Beast Boy and Raven are in the middle of fighting some new villains when Raven discovers she's pregnant. This throws them off balance. They then have to figure out how to protect the baby while still being superheroes. They might have to hide Raven away for a while to keep her and the baby safe. Their relationship also deepens during this time as they face this new challenge together. Eventually, they have the baby, and it becomes a symbol of hope for the future in their world.
One possibility is that the story focuses on how Raven and Beast Boy adjust to being parents. They might face difficulties like protecting their baby from villains who want to use the baby's powers for evil. The baby could also be a key to uniting different factions in their world, so there would be a lot of political intrigue around it as well.
The plot could involve Raven feeling more isolated than usual and retreating into her 'lonely beast' form. Beast Boy, noticing this, decides to try and help her. He might start by just being around her, and gradually they start to communicate more. Eventually, they could face a common enemy together while Raven is still in that form, and their combined efforts lead to a stronger relationship.
It could be Trigon. Since Raven has a connection to him, he might see the baby as a way to get revenge on Raven or as a powerful tool for his evil plans. He could try to corrupt the baby's powers for his own use.
In a fanfiction, it might start with a slow - building tension between Beast Boy and Raven. They could be in a situation where they are forced to be close, like being trapped in a small space. Beast Boy, being the more impulsive of the two, finally gives in to his attraction and kisses Raven on the neck. This then sets off a chain of events where they have to deal with their new - found physical and emotional closeness, as well as how their friends will react.
Perhaps they get trapped in a magical realm where emotions are heightened. Raven, who usually keeps her feelings in check, can't resist the pull towards Beast Boy in this strange place and they kiss. This could then lead to a struggle when they return to normal as they try to figure out if those feelings were real or just a product of the magic.
It could be that a mysterious Christmas spirit visits the Titans. This spirit has a task for Beast Boy and Raven. They have to find three lost Christmas ornaments that are the keys to bringing peace and joy to the city. Along the way, they face various challenges, like a blizzard created by an ice - powered foe. But through their teamwork and growing connection, they manage to find the ornaments and save Christmas.
Well, perhaps it could be about Beast Boy losing control over his powers and fully becoming the beast all the time. Maybe there's a curse or some dark magic at play that forces him into this state.
Perhaps Harry is given the task of mentoring some young Ravenclaw students. As he spends time with them, he starts to appreciate the values of Ravenclaw more. He might learn from them as much as he teaches them, and this could lead to new friendships and a different perspective on the Hogwarts houses in general. Along the way, they could face challenges together, like dealing with a new dark magic threat that targets Ravenclaw specifically.
Maybe in the fanfic, there's a powerful villain who has a device that can nullify superpowers. Beast Boy gets caught in the range of this device and loses his powers. He struggles with feelings of uselessness at first. But then he realizes that his skills as a strategist and his knowledge of the Titans' operations are still valuable, and he uses those to help the team in a different way while also searching for a power restoration method.
One possible analysis is that it explores a unique relationship between two characters. Fanfics often delve into the emotional and romantic aspects that might not be fully explored in the original source. It could show how their different personalities, Raven's more reserved nature and Beast Boy's more exuberant one, interact and create a compelling love story.