It can expand on the theme of surveillance. In the original '1984', we see the omnipresent Big Brother watching. But in fanfic, it might show how the people start to fight back against this surveillance. They could use hidden methods to communicate without being detected, which is an expansion of the idea of resistance against the all - seeing state.
The fanfic expands the story by delving into genetics of magic. In breeding fanfic, we can see how magic is passed on through generations of magical creatures or even wizards. This gives a more in - depth look at the magical world's biological aspects which was not a major focus in the original Harry Potter series. It also allows for new plotlines, like a wizard trying to breed a creature to help in a war against dark forces.
It might expand by creating new spells. For instance, a fanfic could introduce a spell that allows wizards to communicate with portraits from long - dead wizards across great distances.
It might expand the storyline by focusing on the backstories of characters' relationships. For instance, if there's a minor character in the original 'Game of Thrones' who has a brief mention of a love interest, the fanfic could flesh that out. It could show how that relationship started, developed, and influenced the character's actions throughout the main story.
It might introduce new types of magic. For example, it could have a form of magic related to time that was not fully explored in the original. This new magic could have its own set of rules and limitations.
It expands it by delving into the afterlife aspect which the original books didn't fully explore. It can create new settings and scenarios related to the afterlife that add depth to the overall 'Harry Potter' universe.
Another way it could expand is through new locations. The original series had many interesting places, but the fanfic could take us to unexplored areas. Say, a hidden underground city that has been untouched by the outside world for centuries. This new location would come with its own set of rules, mysteries, and threats for the Agents to deal with, thus enriching the overall universe of the story.
Well, it might give more backstory to a character like Jasper. Maybe it delves into his life before he became a vampire, his human experiences that shaped him into the somewhat brooding character we see in Twilight. It could show how his time in the military influenced his self - control and his views on life and death.
The 'Code Geass 5 Year Fanfic' might expand on the original world - building by delving deeper into the politics of the different nations. For example, it could explore how Britannia's rule has changed over the five years, whether there are new rebellions brewing in different regions. It may also focus on the economic aspects. Maybe some regions are suffering more due to Britannia's policies, and this leads to new forms of resistance.
These fanfics can also expand the universe in terms of magic systems. Maybe the combined magic of the characters in the harem creates new spells or magical techniques. The different lineages and magical heritages within the harem can interact in ways that were not explored in the original, leading to a broader and more complex understanding of magic in the Harry Potter universe.
It adds new storylines. The original 'Star Trek' had some episodes dealing with mind control, but fanfics can explore it further. For instance, they can create new alien races that have unique forms of mind control abilities.