How does Cassandra Black fit into the Harry Potter fanfiction universe?

He might be a character who was involved in the politics of the wizarding world. Fanfiction could explore how his influence, either positive or negative, affected the balance of power. And this could in turn impact the events that Harry has to face. For example, if Arcturus Black had made certain alliances, it could change the dynamics of the war against Voldemort.

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.

Another way is that the Black Shuck is a manifestation of an ancient magic that has been long forgotten. A group of students in the fanfiction could discover some old texts about it and decide to investigate. As they dig deeper, they find out that this Black Shuck is connected to a much larger mystery that could change the way they view the history and magic of the wizarding world.

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.