In some Harry Potter fanfics, Rhaegar might be portrayed as a mysterious figure from another realm or time. He could be a mentor - like character, using his wisdom from his own story's context to guide Harry or other characters. For example, he might share his knowledge of magic that is different from what is commonly known in the Harry Potter universe.
Some fanfics may also explore the idea of Rhaegar having some sort of special connection to the magical artifacts or prophecies in the Harry Potter world. Maybe he has a premonition - like ability similar to the seers in the Potterverse, and his presence is related to an ancient magic that needs to be unlocked or understood in order to save the wizarding world from a new threat.
In Harry Potter fanfic, monsters can be portrayed in various ways. Some are depicted as fearsome and menacing, like the traditional view of a werewolf during a full moon. They might be used to create suspense and danger in the story. For example, a basilisk could be lurking in the depths of Hogwarts, ready to petrify anyone who looks into its eyes.
Often, famine in Harry Potter fanfic can be a backdrop to show the social and economic disparities within the wizarding world. Some fanfic authors may depict poorer wizarding families or those on the outskirts of society suffering from famine while the wealthy or those closer to the Ministry seem unaffected. It could also be a factor in driving characters to make desperate choices, like joining a dark cause in exchange for food for their families.
In some Harry Potter fanfics, seduction might be portrayed through the use of magic. For example, a character could use a charm to make themselves more alluring. However, it's important to note that this often goes against the more innocent nature of the original series. Fanfic authors sometimes take creative liberties, but it can be a controversial topic among fans.
In fanfic, the Nundu is often portrayed as a huge, hulking beast with a menacing presence. It's shown as very powerful and its poisonous breath is usually emphasized.
In Harry Potter fanfic, elves are often portrayed in diverse ways. Some fanfics might expand on the house - elves like Dobby and Winky. They could be given more complex personalities, for example, an elf who is not only subservient but also has dreams of freedom and education. Some might show elves with magical abilities beyond what was shown in the original books, like the ability to transform into other creatures momentarily to escape danger.
It's often portrayed as a very alluring potion. In many fanfics, the description of its smell is really detailed. For instance, one character might smell freshly baked cookies (if they have a thing for food or a baker they like) and a particular type of flower that grows in a place special to them.
In some Harry Potter fanfic, incendio is portrayed as a very powerful spell. It can quickly create large and intense fires that are hard to control. For example, a character might struggle to contain the fire they've created with incendio.
In the world of Harry Potter fanfic, sex is not a common or appropriate topic. The source material is centered around the wizarding world, with its unique creatures, spells, and a story of a young wizard's journey. Fanfic writers should be more interested in things like how the wizarding education system could be improved in their stories, or how the characters would react to new magical threats. Sexual content just doesn't fit into this magical universe that J.K. Rowling created for all of us to enjoy as a story of magic, not adult themes.
Ghosts can also be portrayed as tragic figures. Take Moaning Myrtle for instance. Fanfic might expand on her sad story, showing how her death and her state as a ghost are a result of her unfulfilled desires and the pain she endured while alive. They can add a touch of melancholy to the story.
Gluttony could also be depicted in a more symbolic way. A character might be 'gluttonous' for power or knowledge within the wizarding world. They constantly seek more spells, more magical artifacts, without any regard for the consequences. In fanfics, this could be a villainous trait, like a dark wizard who wants to hoard all the powerful magic for himself.