Yes, Black Widow can be in Harry Potter fanfiction. Some fanfiction authors like to create crossovers where they combine different fictional universes. In these crossovers, Black Widow from the Marvel universe might be inserted into the Harry Potter world. For example, she could be a new teacher at Hogwarts with her combat skills and stealth abilities adding an interesting dynamic to the school. Maybe she's there to train the students in a new form of defense or she could be on a mission in the wizarding world related to some sort of magical - technological threat that requires her expertise.
There could be such fanfictions. Fanfiction writers often like to create crossovers between different universes. But finding a good one can be a bit of a challenge. You may have to dig through different categories on fanfiction platforms. Maybe start by looking for crossovers in the Harry Potter section that involve Black Widow. It might take some time to find one that really suits your taste.
I'm not sure of specific examples off - hand, but it could be something like Sirius Black having sudden and uncontrollable outbursts of dark magic due to this 'Black Insanity' in a fanfic.
There's also 'Magic and Espionage: A Potter - Widow Tale'. In this fanfic, Black Widow is somehow transported to the Harry Potter universe and has to navigate the magical world while still using her spy skills. It's really cool to see how she adapts to things like Hogwarts and the Ministry of Magic.
Some fanfictions that are overly long - winded and full of filler content can be considered the worst. They might have pages and pages of a character just thinking about nothing important or going through mundane daily activities that have no real connection to the main plot of the Harry Potter world.
One example could be a fanfic where Harry has the ability to control time without any limits, which is much more powerful than the time - turning devices in the original series. Another might be a story where Voldemort is made invincible and can defeat any opponent with a single spell, completely overpowering the other characters.
One example could be 'The Dominant Potter' where Harry discovers a new and extremely powerful form of magic early on and uses it to take charge in the fight against Voldemort. He is shown as being dominant in strategic planning and combat situations.
One example could be fanfiction that protests the lack of LGBT+ representation in the original Harry Potter series. Writers might create stories where characters are openly LGBT+, exploring their relationships and identities within the Hogwarts setting. Another could be about protesting the way house - elves were depicted. Fanfic authors may write stories where house - elves have more agency and rights, in contrast to their rather subservient portrayal in the books.
Some 'ace' Harry Potter fanfictions include time - travel scenarios. For example, a story where Harry travels back in time to meet the founders of Hogwarts. There are also fanfictions that blend the Harry Potter world with other fictional universes, like a crossover with the world of Narnia. Additionally, fanfictions that delve into the magical creatures in more depth, such as exploring the lives and cultures of the centaurs or the house - elves more thoroughly, are also great examples of the amazing and 'ace' Harry Potter fanfiction out there.
A fanfiction could have Harry Potter accidentally opening a portal to a parallel wizarding world. This regenerates the idea of the wizarding world as we know it by introducing new rules, new magical abilities, and new relationships. The author can then explore how Harry adapts to this new world and how it impacts his understanding of magic and his own identity. It's a great way for fans to expand on the original story in a creative and unexpected way.
A possible example of 'harry potter dissociate fanfiction' is a story where Voldemort's Horcruxes cause dissociation in the wizarding world. The presence of these dark artifacts could be making the magic itself split or act strangely. Wizards and witches might find themselves dissociating from their normal magical abilities or from the magical community as a whole as they try to deal with the chaos caused by the Horcruxes.