One common theme is the exploration of elven magic. Since the official Harry Potter series doesn't go into great detail about elven magic, fanfics often take this opportunity to expand on it.
One great elven Harry Potter fanfic is 'The Elven Alliance'. It weaves an interesting story of how the elves in the Harry Potter universe interact with Harry and his friends. The elves are given more complex personalities and play crucial roles in the plot.
One common theme is the exploration of elven magic. Since the Harry Potter series mainly focuses on wizard magic, fanfics often introduce elven magic as something different and more ancient.
The idea of an elven daughter in Harry Potter fanfiction can also play into the existing relationships in the series. She could interact with the main characters in interesting ways. Maybe she forms a friendship with Hermione, and they exchange knowledge about different magics - the elven magic she knows and the wizarding magic Hermione is well - versed in.
Harry Potter himself can often be a character in such fanfiction. Since he has a lot of unique qualities, fanfic authors might give him elven inheritance to add another layer to his character. Hermione Granger is also common as she is highly intelligent and could use her knowledge to understand and deal with elven magic if she had elven inheritance.
I'm not sure specifically as it depends on the particular fanfiction, but it could be an original character with elven blood who becomes central to the story.
The combination of the magical world of Harry Potter and the mysterious ancient elves makes it unique. The elves in the Harry Potter series already have their own charm, but when we explore their ancient roots in fanfiction, it adds a whole new layer of depth. We can see different interpretations of their magic, culture, and their relationship with the wizarding world.
She could be portrayed as having a very close connection to nature, just like the elves in Tolkien's works. For instance, she might be able to communicate with magical creatures in the Forbidden Forest on a deeper level than other characters.
Well, just based on that title alone, it's difficult to determine its quality. There are so many aspects that make a Harry Potter fanfic great. For example, it could explore new relationships between the characters, or create exciting new magical adventures. But we don't know if 'skull is harry potter fanfic' does any of those things. So, it might be good, it might not.
One interesting concept could be the exploration of how elven blood affects magic in the Harry Potter universe. Maybe it gives unique powers or a different way of casting spells.