She would likely have enhanced senses. Her vision could become sharper, allowing her to see in the dark like the other vampires. Her sense of smell might also improve, which could help her detect the presence of other vampires or even humans from a distance. This could change the power dynamics in the relationships she has with the vampire boys in the story.
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.
In some fanfictions, Yui develops more agency. Instead of just being a passive victim, she starts to fight back against the vampires in a more strategic way. For instance, she might learn how to use their weaknesses against them.
In a fanfiction, Yui and Ayato could go on an adventure together. They might find themselves in a mysterious part of the mansion that no one has explored before. As they face various challenges there, they have to rely on each other. Ayato, who is usually so self - assured, might start to see Yui in a new light as her bravery and determination shine through.
Another way their interactions could be portrayed is through a series of misunderstandings. For instance, Ayato might misinterpret Yui's kindness towards another character as romantic interest. This would lead to some tension between them, but eventually, through communication, they would clear up the misunderstandings and their relationship would reach a new level.
One idea could be that the female OC is a new student at the school. She has a special power that she doesn't fully understand yet. Yui befriends her, and together they try to figure out the secrets of the Sakamaki brothers. The OC's power might attract the brothers' attention in different ways, some being more menacing and some being more curious.
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.
One possible aspect of a Yui x Ayato lemon fanfiction could be the exploration of their complex relationship. In the Diabolik Lovers universe, Yui is often in a vulnerable position while Ayato has his own domineering nature. A fanfiction might delve into how their relationship evolves in a more romantic and steamy way, with the 'lemon' aspect adding an element of passion. It could show Yui gradually coming to terms with her feelings for Ayato despite the difficult circumstances they are in.
One possible aspect of this fanfiction could be the exploration of the complex relationship between Ayato and Yui. In many Diabolik Lovers stories, Ayato is often possessive and Yui is the more submissive figure. In a lemon fanfiction, this dynamic could be intensified in an intimate way. Maybe it shows how Ayato's vampiric nature affects their relationship during these more passionate moments. However, it's important to note that such fanfictions should still adhere to the general themes and boundaries set by the original Diabolik Lovers universe.
Her relationship with the Sakamaki brothers would become more complex. They might see her as both a threat and an equal now. Before, she was just a human for them to toy with, but as a vampire, she could challenge their dominance.