One major theme is the struggle between good and evil. Sanghyuk might be a vampire, but he could have a moral compass that makes him question his vampiric instincts. Also, the theme of identity is prevalent. He has to come to terms with being a vampire, which is different from his former self. This exploration of identity can be really interesting as he tries to find his place in both the human and vampire worlds. There's also often a theme of secrecy, as vampires usually have to keep their true nature hidden from humans.
Love is a common theme. Often, Sanghyuk as a vampire falls in love with a human, creating a forbidden - love scenario. Another theme is power. Vampires are usually powerful creatures, and in these fanfictions, Sanghyuk's power as a vampire is explored, whether it's physical strength or the ability to influence others.
In sanghyuk vampire fanfiction, the theme of immortality is quite common. Sanghyuk, being a vampire, has to deal with living forever. This can lead to feelings of loneliness and a sense of being detached from the normal cycle of life. Another theme is the vampire hierarchy. There are often stories about Sanghyuk's position in the vampire world, whether he's trying to climb the ranks or break free from the constraints of the vampire social structure.
One popular sanghyuk vampire fanfiction is 'The Vampire's Embrace'. It has an interesting plot where Sanghyuk is a vampire struggling to control his urges in a modern world. Another is 'Sanghyuk: Blood and Redemption' which focuses on his journey of self - discovery as a vampire.
One common theme is the struggle with identity. Harry, being a vampire, has to deal with a new side of himself that he may not fully understand at first. For example, in many fics, he has to figure out how to balance his wizard self with his vampire instincts.
One common theme is the struggle between humanity and vampirism. When Ash is involved, it often shows his fight to keep his humanity intact even in the face of vampiric allure.
The theme of the outcast is also prevalent. Despite her power and allure, the vampire seductress is often an outcast in both the human and vampire worlds. Humans fear her, and vampires might be jealous of her power or see her as a threat. This sense of not belonging adds depth to her character and is often explored in different ways in fanfictions. For instance, she might try to find a place where she can be herself, or she might use her outcast status to her advantage by creating her own rules and living on the fringes of society.
Another theme is love and relationships. Since he's a vampire, his relationships with other characters, whether it's romantic or platonic, are often complicated. There might be a love interest who has to come to terms with Todoroki being a vampire, like in 'Todoroki's Vampire Love Affair' where the female lead has to navigate her feelings while also dealing with the danger that comes with Todoroki's vampirism.
A sense of otherworldliness is another theme. Vampire hypnosis fanfiction often plays on the idea that the vampire's world is different from the human world, and the hypnosis is a bridge between the two. In stories like 'The Otherworldly Hypnosis of Vampires', the hypnosis not only affects the human's mind but also gives them glimpses into the vampire's strange and alluring world, full of different rules, powers, and social hierarchies.
The theme of redemption can also be present. Sasuke may have a dark past as a vampire, and through his relationship with Sakura, he may seek redemption. This could involve him trying to control his vampiric urges or make amends for past actions.
In RWBY vampire fanfiction, a frequently seen theme is the clash of cultures. The RWBY world has its own set of values, and vampires bring in their own set of rules and behaviors. This can lead to interesting interactions and conflicts. Another theme is the search for a cure. If a character is turned into a vampire, they or their friends may be on a quest to find a way to reverse the transformation. And the theme of outcasts also exists. Vampires are often seen as outcasts in the RWBY world, and this can be explored in terms of how they deal with being shunned by society and how they form their own communities or try to integrate into the existing ones.
A common theme is the clash of two different worlds. Sonic represents speed, freedom, and heroism, while vampires often symbolize mystery, darkness, and immortality. So, there's often a struggle when these two meet.
One common theme is the struggle between good and evil. Since Willow was originally a good witch, as a vampire, she often battles her new vampire nature which is associated with evil. Another theme is redemption. Many fanfictions explore whether Vampire Willow can be redeemed and return to her former self or at least find a new moral path. Power is also a theme, as being a vampire gives her new powers and she has to learn to control and use them.