A plotline could involve Hei and November 11 getting stranded in a strange and dangerous place. They have to use their skills and wits to survive and find a way back. This could show a different side of their relationship as they depend on each other more than ever.
One possible fanfiction could be about Hei and November 11 teaming up for a dangerous mission. They might face challenges that test their loyalty to each other and the organization they work for. For example, they could be sent to infiltrate an enemy base where they have to rely on each other's unique abilities to succeed.
The mystery surrounding November 11 in Darker than Black provides a rich ground for fanfiction. It has an air of enigma that writers can explore further, like what really happened on that day, what secrets are hidden, etc.
The complex relationship between Amber and Hei makes it interesting. Their personalities are so different yet they are intertwined in the story.
The unique world - building of the original work also contributes. The concept of Contractors and their powers is fascinating. Fanfiction can play around with these powers, creating new power combinations or exploring the limits of existing ones. For example, a fanfic could show a Contractor with a never - seen - before power and how it affects the balance in the 'Darker than Black' world.
Perhaps a plot where an outside force tries to manipulate Hei and Yin's relationship. They have to figure out who is behind it and in the process, they learn more about their own feelings for each other. This could involve some intense action scenes as they are constantly under attack while trying to solve the mystery.
A lot of fanfictions focus on the idea of redemption. Maybe Hei has done something in the context of the story that he needs to make up for, and Misaki plays a role in that process. Also, there's the theme of hidden feelings. Since their relationship in the original anime is somewhat ambiguous, fanfictions like to explore if there are unspoken emotions between them. For example, they might be secretly in love but unable to express it because of their circumstances.
A good antagonist could be a rogue Contractor who has a vendetta against Hei. Maybe this Contractor was once part of the same organization as Hei and feels betrayed. He could have unique powers that pose a real threat to Hei, like the ability to manipulate time in small increments, making it difficult for Hei to land a hit during a fight.
One idea could be exploring Hei's past in more detail. Maybe a story where he has to face a threat from his old organization that forces him to remember things he'd rather forget. Another could be a fanfiction where Hei teams up with an unexpected ally, like a character from a different anime universe, to solve a mystery in the Darker than Black world.
The combination of different story elements from the 'Darker than Black' universe. We get to see HEI in new situations and interacting with various characters he might not have met in the original series.
I think 'darker than black amber and hei fanfiction' might be exploring the darker aspects of the 'Darker than Black' universe. It could focus on the complex characters and their moral gray areas, perhaps with a particular emphasis on Amber and Hei's relationship.