There might be a fanfiction where Yui gets lost in a strange part of the vampire realm and Subaru is the only one who can find her. He battles his own inner demons as well as the external threats to rescue her. This story would show Subaru's protective side towards Yui.
Another interesting plot could be that Yui gets sick, and Subaru is the only one who can take care of her. He has to overcome his own insecurities and fears to be there for her. He might learn more about himself and his feelings for Yui during this time. As he nurses her back to health, their relationship deepens in a more tender and emotional way.
A more unique plot could be set in a modern human world where Subaru and Yui are trying to live a normal life. But Subaru's vampire nature keeps causing problems. They have to figure out how to deal with things like his need for blood in a world where vampires are not supposed to exist. This could lead to some really interesting and emotional moments between them as they struggle to be together.
There are many great authors out there. One author who stands out is 'RosePetalWriter'. Their works often have great character development for Subaru and Yui, and the plots are very engaging.
In some fanfictions, Yui might form an unexpected alliance with a vampire who has been an outcast among the others. This vampire could teach Yui more about their kind, and together they try to change the power dynamics within the vampire household. They might start by uncovering secrets about the origins of the vampires' thirst for Yui's blood, which could lead to a new understanding and a different kind of relationship between Yui and the vampires.
Love and redemption are common themes. Usually, Subaru has a tortured past and Yui's love is seen as a way to redeem him. For example, in many fanfics, Yui's kindness slowly breaks through Subaru's tough exterior.
You can start by looking on fanfiction.net. It has a large collection of fan - created stories for various fandoms, including Diabolik Lovers. Just use the search function and type in 'Diabolik Lovers Yui and Subaru' to find relevant stories.
The relationship can be developed through shared experiences. For instance, if they face a common enemy, like a powerful vampire who wants to harm Yui. As they fight together, Subaru realizes how much he cares for Yui and she starts to see a different, more protective side of him.
One interesting Diabolik Lovers Yui fanfiction could be one where Yui discovers a hidden power within herself and uses it to stand up to the vampires in a more assertive way. It might explore her character development as she breaks free from the typical damsel - in - distress role.
If Yui and Subaru were pregnant in the fanfiction, it could start a whole new arc in the Diabolik Lovers story. The family might be divided on how to handle this situation. Some might see the baby as a new hope or a way to gain more power. Subaru would have to grow up quickly and face his responsibilities. Yui would have to deal with the physical and emotional changes of pregnancy in a world full of danger. Their love for each other could be tested as they navigate through this difficult and unexpected situation.
Well, let's consider each character. Shu would probably be indifferent at first, but as things progress, he might start to worry about how it could disrupt his lazy lifestyle. Ayato would be envious and might try to cause some trouble for Subaru. Laito would make inappropriate comments and try to get a rise out of them. Reiji would be the one trying to keep everything in order and make sure they follow proper procedures. Kanato would be a bit of a wild card, perhaps being overly possessive or acting out. Yui would be relying on Subaru for support, and Subaru would be ready to fight anyone who threatened his family.