One possible scenario could be that Goku Black starts to see the value in the lives he once thought of as insignificant. Maybe he befriends some of the Z - fighters and begins to understand the concept of protecting rather than destroying. For example, he could start to train with Goku and Vegeta, learning their ways and slowly changing his mindset.
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.
Some Dragon Ball - themed forums also often have sections dedicated to fanfiction. Members share their own works or recommend good ones they've read. For example, the Kanzenshuu forums might have some great Goku and Black Goku fanfiction.
Well, I've come across a few. Some explore Goku Black's relationship with Goten in really unique ways. For example, there are stories where Goku Black has a change of heart due to his interactions with Goten. It's really fascinating to see how different authors play with their characters' personalities and the overall Dragon Ball universe in these fanfictions.
Another characteristic is the expansion of the Goku Black universe. It could introduce new powers for Goku Black, or new versions of the characters he interacts with. For instance, a fanfiction might give him a new transformation that is unique to that story. The best Goku Black fanfictions also manage to stay true to the essence of his character while still bringing something new and exciting to the table.
One good fanfiction is 'The Blackened Saiyan' which explores Goku Black's journey in an alternate universe with a lot of in - depth character analysis. Another is 'Goku vs Goku Black: Redefined' that has some amazing power - up battles between the two. 'Black's New Purpose' is also great as it gives Goku Black a different motive than just pure evil.
Another factor is the plot. It needs to be engaging. Maybe it could explore Goku Black's origin in a new way or have him face off against the Z - fighters in creative battles. A fanfiction that has a good balance between action, character development, and plot twists can be really great. For instance, if it shows how Goku Black's actions affect the different planets in the Dragon Ball Z cosmos, that would add depth to the story.
Yes, there are some out there. You can start by looking on fanfiction websites like Archive of Our Own. Just search for 'goku x black widow' and you'll find various stories. Some might be action - packed adventures where they team up across different universes, while others could explore a more romantic side of their relationship.