Another theme is the relationship with other vampires or those in the wizarding world who are aware of his condition. There are often power dynamics and trust issues at play. For example, in some fanfictions, Severitus has to hide his vampire identity from his friends at Hogwarts. This leads to a lot of secrecy and tense moments. The exploration of his newfound powers as a vampire is also a popular theme. He may have to learn how to control his thirst for blood while also using his enhanced abilities for good or evil, depending on the story's direction.
One popular Vampire Severitus fanfiction is 'The Blood Bond'. It has an interesting plot where Severitus has a unique connection with the vampire world. The character development is quite engaging.
In my opinion, the best Severitus fanfictions are those that explore unique scenarios. Maybe it's a different take on how Snape discovers he has a father - like role towards Harry. It could also be about how they overcome their initial animosity in a really creative way. Good grammar and spelling are also important, as they make the reading experience smooth. And of course, a well - paced plot that keeps you hooked from start to finish.
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.