The themes can be quite diverse. There's the theme of spiritual growth. In some 'After Death' fanfics, Harry's spirit grows and learns new things in the afterlife. Then there's the theme of justice. For instance, if there were wrongs not set right during Harry's life, some fanfictions will show how they are addressed after his death. And a very interesting theme is the connection between the living and the dead. How the dead can still influence the living in the Potter universe is a fascinating concept explored in many fanfictions.
One popular theme is the 'what if' scenarios. Like what if Harry had been sorted into Slytherin? This allows writers to explore different character arcs and how the story would have changed. Another is the romantic relationships. Fans often write about different pairings, such as Hermione and Draco, exploring how their personalities would interact in a romantic context.
Sirius Black is a very popular character in such fanfiction. Since his death was quite tragic in the original series, many fanfictions explore his afterlife and his possible return or influence on the living. Also, Dumbledore, as a very powerful and wise wizard, often appears in these fanfictions, perhaps guiding the living from beyond the grave or having some unfinished business in the afterlife.
Well, a frequent theme is redemption. Characters who may have made mistakes or been on the wrong side in the original story might seek redemption in the face of death. It could be a Death Eater realizing the error of their ways at the last moment. Another common thing is the power of love even in death. Love was a strong force in the original Harry Potter books, and in these fanfictions, it might be shown as something that can transcend death, like a character's love for another still having an impact even after they're gone. And then there's the theme of mystery. The circumstances around a character's death might be shrouded in mystery, and the fanfiction could be all about uncovering the truth.
One of the most popular themes is alternate universes. Fans love to imagine what would happen if certain events in the original story were different. Another popular theme is character relationships, especially the romantic relationships between characters like Harry and Hermione, which deviate from the original pairings. And of course, there are a lot of fanfictions that focus on the dark side of the wizarding world, exploring how Voldemort could have been even more menacing or what other dark wizards might be out there.
One popular theme is identity. Since Metamorphmagi can change their appearance, fanfictions often explore how this affects their sense of self. Another theme is secrecy. They might have to hide their ability, which creates interesting plotlines.
One of the popular elemental themes is the use of fire. It often represents power and passion. Many fanfictions have characters who can conjure and control fire in unique ways, like creating phoenix - like flames. It gives a sense of danger and intensity to the story.
One of the most popular themes is the 'What if' scenarios. For example, what if Harry had been sorted into Slytherin? Another common theme is the exploration of character backstories that J.K. Rowling didn't fully delve into in the original books, like the early life of Severus Snape. And relationships, not just romantic ones but also friendships, are often explored in-depth. For instance, the friendship between Harry, Ron and Hermione from different perspectives.
One popular theme is the clash of cultures. The very different natures of the wizarding world and the Xenomorphs' universe make for an interesting contrast. Another is survival, as characters from the Harry Potter world have to figure out how to survive against the deadly Xenomorphs. And of course, there's the theme of magic vs. brute force, as the wizards' spells are pitted against the Xenomorphs' physical strength and reproductive abilities.
The theme of Tonks' love life is quite common. Whether it's her relationship with Remus Lupin or other potential partners, it's a big draw for readers. Also, her friendship with other characters, like Hermione or Ginny, is often explored. For example, fanfictions might show them going on adventures together or helping each other out in difficult situations. Additionally, Tonks' role in the fight against Voldemort is a recurring theme, highlighting her courage and magical skills.
One popular theme is Blaise's family history. Given that his family has a mysterious background in the original series, many fanfictions explore it further, like how his family's past affects his present at Hogwarts.