Well, a plotline might involve Snape trying to protect Draco more secretly. Since Draco is his son, he could be more involved in Draco's Hogwarts life. Also, there could be a plotline where Draco starts to question his identity and values. He has been raised as a Malfoy, but now with this new knowledge, he might try to understand Snape's side of things, like his loyalty to Dumbledore.
In some fanfictions, a possible plotline is that Draco's magical abilities start to change or develop in a different way because of his true parentage. There could also be a plotline where the relationship between Draco and Harry takes a different turn. Instead of being rivals, they might have to work together because of Draco's connection to Snape, who was an important figure in the fight against Voldemort. And there could be a plot where the wizarding world has to accept this new family connection, which could cause a stir among the pure - blood families.
Well, a plotline could involve Harry finding out about his true parentage through some hidden clues or a magical revelation. This could lead to a major identity crisis for him as he has to reconcile his new - found connection to Snape with his existing relationships. Also, the wizarding community's reaction to this revelation would be an interesting aspect. Some might be outraged, while others might see it as a chance for a new beginning between the two families.
One possible plotline could be Draco finding out about his true parentage and having to keep it a secret from the Death Eaters who expect him to follow in Lucius' footsteps. He might start to question his loyalties and gradually side with the Order of the Phoenix.
Another plotline could involve a power struggle. Since Draco comes from a wealthy and influential pure - blood family and Snape has his own position of power within Hogwarts. Their shared interest in Hermione could lead to a competition not just for her affection, but also in terms of status and influence. For example, they might try to outdo each other in protecting Hermione from some external threat, which in turn might make Hermione see different sides of both of them.
Another plotline could be that they are all given a mysterious task by an ancient magic entity. To complete this task, they must put aside their differences. Snape and Lucius, who have a history of being on the same side but also having their own rivalries, have to work with Harry, whom they have long seen as an adversary. Draco, caught in the middle, has to choose between his family's old ways and this new alliance, which creates a lot of internal conflict and an engaging story.
One plotline could center around them adopting a child. Given their complex backgrounds, they would face unique challenges in raising a child. They might have to deal with the child being bullied because of their fathers' history. The fanfiction could show how they support each other and the child through these difficult times. Also, they could go on adventures together as a family, exploring parts of the wizarding world that are not well - known. It could be a way for them to bond and create new memories away from the prying eyes of the wizarding society.
One main theme is identity. They have to come to terms with being related to Snape and how that changes their self - perception. Another is family, as they navigate their new family structure.
One possible plotline could be Sebastian's struggle with his identity. Having two very different fathers in Snape and Sirius, he might feel torn between their respective legacies. He could inherit Snape's intelligence and Sirius's rebellious spirit. For example, at Hogwarts, he might be sorted into a house that neither of his fathers were in, and have to find his own path within the school while dealing with the expectations that come with his parentage.
One common plotline is that Draco inherits some sort of ancient magic or a powerful artifact that gives him control over Harry. Another is that a dark wizard forces Draco to be Harry's master as part of a devious plan. Maybe to turn Harry to the dark side or use him for some evil purpose. And sometimes, it's just a result of a magical accident that binds them in this master - servant relationship.
Well, Snape might heal Draco because of his own sense of morality. Despite his dark exterior, Snape has a code of ethics. Draco is still a student, and Snape may believe that every student should be given the chance to survive and learn from their mistakes. Additionally, Snape could be acting on behalf of Dumbledore in some way. Dumbledore often had complex plans, and Snape was his agent. Healing Draco could be part of a bigger plan to keep the balance in the wizarding world.
One possible plotline could be Snape revealing the truth to Harry in a moment of crisis. Maybe when Harry is about to face Voldemort alone, Snape steps in and tells him the truth, giving Harry a new motivation to fight.