The plot could revolve around a shared threat that forces Zamasu and Shin to team up. Maybe an even more powerful and malevolent force arrives in their universe. At first, they are hesitant to work together, but as the situation worsens, they have no choice. During their time together, they gradually develop a grudging respect for each other. Zamasu could be impressed by Shin's unwavering loyalty to his cause, and Shin could see some good in Zamasu's power, if it were redirected towards a positive end.
For Zamasu, give him moments of self - reflection. Let him question his own beliefs when faced with Shin's different perspective. For example, when Shin shows him acts of great kindness by mortals that Zamasu has overlooked. For Shin, put him in situations where he has to make tough choices that challenge his loyalty. This could cause him to reevaluate his own character. As the story unfolds, Zamasu could develop a newfound sense of empathy, and Shin could become more assertive in his beliefs and actions.
A good exploration of their personalities is key. Since they both have distinct traits, seeing how they interact based on who they are is important. For example, Zamasu's self - righteousness and Black's more primal power.
A common theme is power - seeking. They are often depicted as constantly striving for more power and ruling over the universe. Another theme is their unique bond, whether it's a friendship or a more sinister partnership.
Love is a very common theme. Writers often explore how lee shin and shin chae kyeong fall in love, or how their love overcomes various obstacles. Another common theme is friendship, as their relationship might start as friends and then develop into something more.
Another option for the main antagonist could be Beerus. As a God of Destruction, he wouldn't be happy with Zamasu and Goku Black causing chaos. Beerus is extremely powerful and has the authority to deal with threats to the universe. He might see their actions as a direct challenge to his power and order. If he gets involved, he could completely change the dynamic of the story, as his power level is on a whole different scale compared to most characters in the Dragon Ball universe.
There's also 'Zamasu and Black: A Forbidden Bond'. This fanfiction focuses on the more emotional side of their relationship. It shows how they might have come to understand each other on a deeper level, despite their differences. It's really well - written and the characterizations are on point.
One great place to find lee shin x shin chae kyeong fanfiction is on fanfiction.net. There are many stories there that explore their relationship in different ways. Some might focus on their adventures together, while others might delve into their more emotional and romantic interactions.
One idea could be a crossover with the Dragon Ball Super universe and the DC Comics universe. Zamasu could team up with Darkseid, believing they share a similar view of bringing 'order' to their respective realms. Another idea is a crossover with the Naruto universe, where Zamasu tries to impose his will on the ninja world, facing off against powerful shinobi like Naruto and Sasuke. Or perhaps a crossover with the Star Wars universe, with Zamasu as a Sith - like figure, trying to gain control over the Force.
One idea could be exploring their relationship in an alternate universe where they succeed in their plans. Another could be a story where Goku Black has a change of heart due to his connection with Zamasu and tries to stop their destructive ways. Maybe a plot where they face a new enemy that forces them to reevaluate their alliance.