Common themes include the struggle between normal life and the supernatural. The daughter may want a normal life but is constantly drawn into the battles like Buffy was. Another is the theme of mentorship. Buffy may mentor her daughter in slaying, or the daughter may find other mentors. There's also the theme of redemption. If the daughter makes mistakes or has a dark side, she may seek redemption, much like some of the characters in the original Buffy series did. These themes help to create interesting and engaging stories in the fanfiction world.
One common theme is the passing on of the slayer legacy. The adult daughter might struggle with the expectations and powers that come with being related to Buffy. For example, she may have to learn how to control her emerging slayer abilities while also dealing with the normal pressures of adulthood.
I'm not sure which specific Buffy adult daughter fanfiction is the best as there are so many out there. However, you can start by looking at popular fanfiction platforms. Some fanfics might focus on the family dynamics between Buffy and her daughter, like how they communicate and resolve conflicts. Others could be more action - oriented, with the daughter following in Buffy's footsteps as a slayer. You should also check the reviews and ratings of different fanfictions to find the ones that suit your taste.
A rogue slayer who has turned to the dark side. She might envy Buffy's daughter's connection to Buffy and the legacy she represents. This rogue slayer could be using her powers for evil, like causing chaos in the human world and trying to eliminate any competition, which includes Buffy's daughter.
Another way is to look at Buffy fanfiction anthologies or collections. Although they might not be specifically dedicated to the concept of Buffy's adult daughter, there could be stories within them that touch on this theme. Check with Buffy fanfiction publishers or online groups that curate such collections.
One idea could be that Buffy's adult daughter discovers she has a unique slayer - like power that is different from her mother's. She could struggle to come to terms with it while also trying to live a normal life, like having a regular job and relationships. Maybe she meets a group of new allies who help her understand and control her powers.
Some popular themes might include alternative universes where Buffy has different powers or relationships. Another could be exploring her deeper emotional connections with other characters in a more in - depth way than in the original series.
One common theme is the complex relationship between Buffy and Angel. It could be about their unfulfilled love, the challenges they face in being together because of their different natures (Buffy as the slayer and Angel as a vampire with a soul).
There are some fanfiction websites like Archive of Our Own (AO3). It has a large collection of Buffy - related fanfiction, including different ratings and themes.
Some common themes could be alternate universes where the characters have different relationships or roles. For example, a theme might be a world where Buffy becomes a vampire herself. Another could be exploring deeper relationships between the main characters that were only hinted at in the original show, like a more in - depth look at the friendship between Xander and Willow.