The storyline could involve Harry Potter, now as Goku Black, entering the Dragon Ball universe. He could meet the Z - fighters and they would be both confused and intrigued by this strange new being. Harry might have to prove himself not to be a threat, all while dealing with his own internal conflict of having this new, more aggressive form. He could also bring some of his Hogwarts friends with him, like Hermione, who could try to find a way to reverse the transformation using her vast knowledge of magic.
Well, one possibility could be that Harry Potter, through some sort of magical accident or powerful spell, gets transformed into Goku Black. He might then use his newfound Saiyan powers along with his wizarding knowledge. For example, he could use magic to enhance his ki blasts or use ki to perform spells in a more powerful way. He might also struggle with the evil tendencies of Goku Black while trying to hold on to his own moral compass as Harry Potter.
His magic might become more physical. Instead of just waving a wand, he could use ki to direct spells. For example, his Patronus charm could be charged with ki energy, making it stronger and more tangible. Maybe his spells would be instant like Goku Black's attacks, no need for long incantations.
First, you need to figure out how to bring the two universes together. Decide on a way for Goku Black to enter the Harry Potter world, like a magical portal or some kind of interdimensional rift. Then, think about how the characters will react to each other. Harry and his friends will be very different from the characters Goku Black is used to. You should also consider the power levels. Goku Black is extremely powerful, so how will the wizards' magic compare? You can start with a simple plot idea, like Goku Black being lost in the wizarding world and needing help to get back home.
It could be a really wild and interesting story. Maybe Goku Black could end up at Hogwarts somehow. He might use his power to either cause chaos or try to take over the wizarding world. And the wizards would have to use their magic in ways they've never thought of to fight him.
One great fanfiction could be the one that explores Harry's journey into becoming Lord Black in a way that stays true to the essence of the Harry Potter universe. It might involve him inheriting the Black family legacy, dealing with the dark family secrets, and using his own Gryffindor values to reshape the Black family's reputation. For example, he could start by exploring the Black family library and uncovering ancient magic that was once associated with the family, but use it for good.
Well, he might gain a lot of power and influence within the wizarding world. He could use his new position to make changes in the way pure - blood families operate. For example, he could try to break down the traditional pure - blood elitism and promote more equality among wizards and witches, just like he always stands for justice.
If Harry Potter becomes Lord Slytherin, he might bring about a new era of unity in Hogwarts. Since he has friends from different houses, he could bridge the gap between Slytherin and the other houses. He may introduce new rules or traditions within the Slytherin house that are more inclusive. For example, he could encourage more cooperation in Quidditch matches instead of the cut - throat competition that has been the norm. Also, his magical abilities, which are already quite remarkable, could be enhanced or used in different ways as Lord Slytherin, perhaps leading to new spells or ways of magic being discovered.
The storyline could start with a strange magical accident that creates a portal between the Harry Potter universe and the Marvel universe where Black Widow exists. Harry stumbles through this portal and meets Natasha. At first, they are suspicious of each other but soon realize they have a common goal of fighting evil. As they work together, they develop feelings for each other and eventually decide to get married.
I'd say it's quite unique. Usually, fanfictions tend to stay within the same universe or at least related universes. But Harry Potter and Goku are so different. Harry has his wand and spells, while Goku has his ki blasts and transformations. So when you put them together like this in a fanfiction, it stands out as something different and not very common.
It might be a story where Harry Potter, while exploring different magical texts or spells, stumbles upon a connection to the world of Goku. He starts to study Goku's fighting techniques and tries to incorporate them into his dueling skills. For example, he could learn about Goku's ki control and try to find a magical equivalent in the wizarding world. And he would be constantly in awe of Goku's ability to overcome seemingly impossible odds.
I'm not sure of a specific one off the top of my head, but generally, a good fanfiction with this premise would likely show Harry having to adapt to the new status and responsibilities. He'd probably have to deal with the prejudices of the pure - blood society as Lord Black. It might also involve him making changes to the Black family's traditional ways of doing things.