Another theme is the development of an unusual relationship. The OC is not a canon character, so their relationship with Sherlock has to be built from scratch. It can range from a mentor - mentee relationship to a romantic one. A lot of fanfictions explore how two very different personalities can come together and form a strong bond.
Self - discovery is also a theme. The OC, being in Sherlock's world, often discovers new things about themselves. They might find out that they are braver or more intelligent than they thought. And Sherlock, through his interactions with the OC, might also learn something about his own emotions or the way he views the world around him.
One common theme is mystery. Since Sherlock is all about solving mysteries, the OC often gets involved in his cases. For example, in many fanfictions, the OC might have some inside knowledge or a unique way of looking at the clues that helps Sherlock solve the mystery faster.
The theme of power dynamics is often explored. Sherlock is a very intelligent and dominant character, and the OC may either challenge that or submit to it. This creates tension and interesting plotlines. For example, an OC who is just as intelligent as Sherlock may constantly compete with him, leading to a battle of wits that is exciting to read.
Mystery is also a big theme. Since Sherlock is a detective, the fanfictions usually involve some sort of mystery that the couple has to solve together. This not only adds to the plot but also strengthens their bond as they work through it. For instance, in some stories, they are on the hunt for a serial killer.
One common theme is the bond between the OC and Sherlock. It's often about how the OC comes to care deeply for Sherlock and is willing to put themselves in danger to protect him.
One common theme is the battle of wits. Sherlock and Irene are both highly intelligent characters, and fanfictions often focus on their mental sparring. For example, in many stories, they try to outguess each other's plans.
One common theme is the deep friendship that develops into something more. It often shows how their initial acquaintance grows into an unbreakable bond. For example, in many fics, they start as flatmates and gradually realize their feelings for each other.
One common theme is family drama. Their relationship as siblings is full of mystery and conflict, which makes for great storytelling. For example, in many fanfictions, they struggle to come to terms with their shared past.
A theme that often appears is the protection they have for each other. In fanfictions, you'll see Sherlock going to great lengths to protect John, and vice versa. It shows the strength of their bond. Also, the theme of self - discovery is common. Both John and Sherlock learn more about themselves as they navigate their relationship in these stories.
One common theme is friendship. Their bond is often explored in great depth, like how they rely on each other in difficult situations. Another is loyalty. Fanfictions usually show how they are always there for one another no matter what. For example, in some stories, Watson stays by Sherlock's side even when others turn against him.
Friendship is a very common theme. They often show how Sherlock and Marcus Bell form a strong bond despite their differences.
Another theme is the mystery - solving aspect. Fanfictions usually have them working together to crack cases, with Holmes' brilliant mind and Watson's practical knowledge. In 'The Mystery of the Missing Heirloom' fanfiction, they use their combined skills to find the heirloom. Watson provides medical insights that help Holmes piece together the clues.