In fanfic, the idea of Draco and Hermione being pregnant could stem from the exploration of redemption arcs. Draco, who was initially a bully and on the wrong side, might be going through a process of change. Hermione, with her kind heart, could be the one to see this change in him. Their relationship might develop slowly as they start to understand each other better. As they grow closer, the pregnancy could be a way to show the extreme consequences of their relationship in the fanfic world, as well as a symbol of a new beginning that combines the two formerly opposed sides.
No, it's not a common type. In the Harry Potter fanfic world, there are more common themes like the exploration of the original friendships and relationships in a different light, or the creation of new adventures for the characters. A 'Draco gets Hermione pregnant' scenario is quite far - fetched from the original story and goes against the typical relationship between the two characters, so it's not as prevalent as other types of fanfics.
Maybe in that fanfic's plot, there was a misunderstanding that got out of hand. Suppose Harry was framed for something terrible, and Hermione, believing the false evidence, felt that she had to take drastic action to protect the wizarding world from what she thought was a great threat, so she kills him. But later she realizes her mistake.
There could be a situation where Draco has a change of heart later. Maybe he realizes his mistake after some time away and tries to come back into Hermione's life. This could lead to a very emotional and complex reunion, with Hermione having to decide whether to forgive him or not.
Perhaps the collar is a cursed object that Hermione and Harry need to deal with. It could be causing strange behavior among the students. For instance, those who touch it start acting like animals. Hermione would use her extensive knowledge of magic to research a solution, while Harry would be more hands - on, trying to keep the affected students safe.
One common theme is the clash of two different worlds. Draco comes from a family with a long history of dark magic associations, while Hermione is a muggle - born witch who is very much on the side of the light. Their pregnancy could symbolize the merging of these two worlds. Another theme could be about acceptance. How the wizarding community reacts to their relationship and the pregnancy is often explored. It could be full of shock, disbelief, and gradually acceptance as the story progresses.
One possibility is that they exchange very personal and heartfelt gifts. Hermione might give Draco a book that has special significance to their relationship, and Draco could present her with a piece of jewelry that was passed down in his family. They would then spend the night just enjoying each other's company, looking at old photos and sharing stories from their Hogwarts days.
In some fanfictions, Hermione might betray Harry due to a misunderstanding. For example, if there were false rumors spread about Harry being involved in dark magic or having a secret, evil plan. Hermione, being a stickler for the rules and the greater good in the original series, might be misled into believing these rumors and thus betray Harry.
One possibility is that Hermione's relatives could introduce Harry to a different side of the wizarding world. They could have unique magical items or knowledge that is not commonly known. Harry might also be involved in some family - related magic rituals or celebrations. This could lead to new adventures and experiences for Harry, and also strengthen his bond with Hermione as they share these new aspects of her family life together.
If Hermione and Draco were siblings in fanfiction, it would completely turn the original story on its head. For one, Hermione's Gryffindor nature and Draco's Slytherin one would create a really interesting family dynamic. Their parents must have had a very complex relationship for this to be possible. It could lead to Hermione having a different view of the wizarding world from the start. Instead of being a Muggle - born advocate in the way she was, she might have had some internal conflict due to her Slytherin - influenced family ties. And Draco might not be as much of a bully as he was originally, or at least he would have a different kind of relationship with Harry, Ron, and Hermione.
They would become more reliant on each other. Their relationship would shift from just being friends to co - parents. There would be a deeper level of intimacy and shared responsibility.