Another theme might be adventure. The little sister could get involved in some sort of adventure, and Shizuo has to come to her rescue or be part of the adventure with her. It adds an element of excitement and action to the story.
Growth and self - discovery can also be a theme. The little sister may be on a journey to discover herself, her powers (if in a supernatural setting related to the original source), or her place in the world. Shizuo's presence can either support or complicate this process, and this exploration of character development can be an interesting theme in such fanfiction.
One common theme could be family dynamics. Since it involves Shizuo and his little sister, exploring their relationship, how they interact, protect each other or have conflicts can be a central theme.
Another theme is the redemption arc. If one of the characters, say Masaomi, has made some mistakes in the past, the fanfiction might focus on how Shizuo helps him to redeem himself. Or vice versa. This can involve Shizuo learning to control his anger better with Masaomi's influence, and Masaomi becoming a more honest and trustworthy person through his relationship with Shizuo. It's all about how their relationship can be a catalyst for personal growth for both characters.
Another theme is the idea of protection. Shizuo is often depicted as protecting the reader from various threats in the city. This could be from other dangerous characters or just the general chaos of their world. It gives a sense of security in their relationship.
One common theme is the 'opposites attract' concept. Given their very different personalities, this is often explored. Shizuo's brute strength and hot - headedness contrasted with Mikado's intelligence and calm demeanor makes for an interesting dynamic. Another theme could be the idea of protection. Shizuo might be seen as protecting Mikado from the various dangers in Ikebukuro's underworld.
A big theme is also the transformation of the reader's perception. At first, the reader might be scared or wary of Shizuo because he's a vampire. But as the story progresses, they start to see him in a different light, maybe even falling in love with him. There's also the theme of the vampire world itself. Writers often describe the rules, the hierarchy, and the culture of the vampires which the reader has to navigate through.
Another theme is the exploration of an unlikely relationship. Since Shizuo is such a complex and often violent character, seeing him interact with an original character creates a unique dynamic. It's about two different worlds colliding, like in some fics where the OC is from a completely different background than the Durarara world.
I'm not sure of specific 'Shizuo little sister fanfiction' titles off - hand. You could try searching on fanfiction - dedicated websites like Archive of Our Own. They usually have a wide variety of fan - created works.
Family is a common theme. The relationship between Hiccup and his little sister, whether it's full of love, rivalry, or a bit of both. Another theme is adventure. Since they live in a world with dragons, the sister often goes on exciting adventures.
Another theme is growth. The little sister often grows and learns from her experiences with BTS. For instance, she might learn about the music industry, how to deal with fans, and how to become more confident. It's like she's on a journey of self - discovery with the help of her brothers. This is often shown through different events and interactions in the story.
A common theme is family. Since she's Percy's sister, stories often explore their sibling relationship, like how they support each other or have occasional disagreements. Another theme is the discovery of her own identity as a demigod.
Well, in many of these fanfictions, the theme of fitting in is present. She might struggle to find her place among Archie's friends or in the school environment. Another common theme is the exploration of her talents. Whether it's music, writing, or something else, these stories often show her developing and using her skills. And the theme of loyalty is there too, loyalty to her family and friends.