She could fit as a new kind of magical being. For instance, she might have powers that are related to time and space, which is different from the typical magic in the Harry Potter world. This would make her a mystery for the characters to figure out, like Hermione would be eager to study her abilities.
The female Alduin could be a part of an ancient prophecy in the Harry Potter fanfiction. Her arrival at Hogwarts could be the sign that a great change is about to happen in the wizarding world. Maybe she has the power to either save it from a new, unknown threat or accidentally bring about chaos depending on the choices she makes.
She might be a bridge between the wizarding world and another dimension where Alduin comes from. In the fanfiction, this could lead to new magical knowledge and spells being introduced. Her character could also introduce new cultural elements, like different ways of casting magic or different magical artifacts that are unique to her world. Harry and his friends would then have to learn about these new things to either help her or protect their own world from any potential danger.
In fanfiction, umbramancy can fit in by being a long - lost or forgotten magic. It could be something that was once used by ancient wizards but lost over time. For example, it might be rediscovered in the Forbidden Forest by a curious student.
Nyarlathotep could be a new, powerful and malevolent force that disrupts the balance of the Harry Potter universe. He might be an entity from a different dimension that finds its way into the wizarding world, causing chaos.
Cortana might be seen as a powerful magical tool in the Harry Potter fanfiction world. Some might write that she has the power to enhance a wizard's magic. Imagine a wizard using Cortana to boost the power of their spells. She could also be used to store magical knowledge, like a magical hard drive, and wizards could access this knowledge to learn new spells or techniques.
Mithril might be incorporated into the fanfiction as a material that has a special connection to certain magical creatures. Maybe unicorns are attracted to Mithril, and a plot could revolve around a group of students trying to use Mithril to lure a unicorn to safety from a poacher. Along the way, they learn more about the magical properties of Mithril and how it interacts with the magic of the unicorn, which in turn could have implications for other areas of magic within the 'Harry Potter' universe.
Freerunning can fit into the Harry Potter universe by adding a new dimension to movement. For example, it can be used for escaping from dark wizards in the narrow alleys of Diagon Alley or Hogsmeade. The characters can use their parkour skills to quickly jump over obstacles and get to safety.
Illumi can fit in as an outsider with unique skills. His combat and stealth abilities are not like anything in the wizarding world, so he could be a wildcard. For instance, in some fanfictions, he might be seen as a new kind of threat or an unexpected ally to the Order of the Phoenix.
Astoria Greengrass often serves as a bridge between different storylines. She can be used to explore the post - war Slytherin perspective. For example, in some fanfictions, she helps to heal the rift between Slytherin and the other houses.
The Sharingan can fit by enhancing a character's perception. In fanfiction, it could make a wizard like Harry more aware of his surroundings during duels. He could see the flow of magic more clearly, similar to how in the Naruto universe, Sharingan users can see chakra.
In Harry Potter fanfiction, the concept of concubine can be a way to explore different cultural or historical aspects within the wizarding world. It could be used to show a more complex social structure.
Well, in fanfiction, Merlin might be reincarnated in the Harry Potter era. He could retain some of his past memories and powers. As a character, he would bring a different style of magic, one that is more in tune with nature and less structured compared to what the wizards in Harry's world are used to. His arrival could cause a stir among the magical community, with some seeing him as a savior and others as a threat, all while having a special connection with Harry, perhaps as a mentor or a long - lost relative in the magical sense.