I think mystery is a very common theme. Since Conan is a detective - themed anime, in Conan Dan Ran fanfics, the mystery element can be enhanced. Writers can create complex cases for Conan, Dan, and Ran to solve together. Love is also a major theme. Fans might explore the romantic relationships between the characters in different ways. It could be about unrequited love or the development of a new relationship. And the theme of growth is possible too. The characters can grow in terms of their skills, understanding of the world, and emotional maturity as the fanfic progresses.
First, know the characters well. Conan is a brilliant detective, Ran is a strong - willed girl, and Dan (assuming it's a character in the context). Understand their personalities, motives, and relationships. Then, create an interesting plot. It could start with a mystery or a problem that they need to solve. For example, a new type of criminal case that has stumped the police. Next, use vivid descriptions. Describe the scenes, like the dark alleys where the mystery unfolds or the cozy living rooms where they discuss their findings. Also, add some emotional depth to the story. Maybe Ran has some inner conflict about her feelings for Conan. Finally, make sure the dialogue is natural. The characters should talk like they do in the original series.
A frequently seen theme is the idea of a shared destiny. Fanfic writers often emphasize how Conan and Ran are meant to be together despite all the obstacles in their way. The concept of trust is also common, as Ran has to trust Conan even when she doesn't fully understand his actions sometimes. And of course, there's the theme of their love story, which is often told in a more elaborate and sometimes alternate way compared to the original anime.
The popularity of Detective Conan x Ran fanfictions lies in the strong existing relationship between the two characters in the original series. Fans are always curious about how their relationship could develop further, like if Ran will finally figure out Conan's true identity. Also, the mystery and adventure elements in the original show can be carried over into the fanfictions in unique ways.
A popular theme is the anticipation and excitement. In these fanfictions, the characters of Dan and Runo may be depicted as eagerly awaiting the arrival of their baby. They might start planning the nursery, picking out baby names, and imagining their future as parents. It gives a positive and heartwarming feel to the story. Also, some fanfictions may touch on the challenges they face, like Runo having to deal with morning sickness and Dan trying to be as helpful as possible during this time.
In many Fate female Shirou fanfics, the theme of redemption often appears. Given the complex nature of the Fate universe with all its battles and moral ambiguities, a female Shirou might have her own path towards redemption. Maybe she made some mistakes in her past battles or in her relationships with other characters. Another common theme is her adaptation to the Fate world. The world of Fate is filled with rules, magic systems, and various factions. A female Shirou could be depicted as trying to understand and adapt to these, which makes for an interesting story as she might face different challenges compared to her male counterpart.
In these fanfics, the theme of teamwork is everywhere. Ben and Rook are a team, and exploring how they work together, divide tasks, and combine their skills is a big draw. For example, Ben's brute force with his alien powers and Rook's strategic thinking. Additionally, the theme of facing fears comes up a lot. Both characters have their own fears, and seeing them overcome those in the fanfictions is quite appealing. And of course, the theme of exploring new planets and civilizations, which is a natural extension of Ben's alien - transforming abilities and their intergalactic adventures.
One of the most popular themes is mystery and detective work. Sherlock Holmes, the main character in many of Doyle's novels, is a brilliant detective who solves complex cases. Another theme is the Victorian era setting which adds a lot of charm and historical context. Also, the theme of friendship, like the relationship between Holmes and Watson, is quite prominent.
One of the popular themes is the forbidden love aspect. Since Jungkook is a vampire, there's often a story of him falling in love with a human, which is against the vampire rules in many of these fanfic universes. Another theme could be the struggle with his vampire nature. He might be fighting his urge to feed on blood while trying to maintain a normal life or relationship. And sometimes, the theme of vampire clans and power struggles within them is also explored with Jungkook being in the middle of it all.
One popular theme is the rivalry between Sonic and Metal Sonic. Writers often explore how Metal Sonic tries to outdo Sonic in various challenges. Another theme could be the idea of Metal Sonic developing his own sense of self or identity, different from just being a copy of Sonic. And sometimes, there are fanfics that focus on their unlikely alliances in the face of a greater threat to their world.
One of the most popular themes is 'What if' scenarios. For example, what if Harry had been sorted into Slytherin? This allows for a whole new exploration of his character and relationships. Another theme is the post - Hogwarts life of the characters. Fans love to imagine how Harry, Hermione, and Ron navigate the wizarding world as adults. And of course, the exploration of the Marauders' era through the eyes of the new generation is also very popular as it combines the nostalgia of the original series with new storylines.