Another theme might be the growth of their relationship over time. Maybe at first they start off on a rocky or tense note, but as the story progresses, they come to understand and care for each other more deeply. There could also be themes related to the challenges they face together, whether it's external threats or internal struggles within their relationship.
Often, there can be themes of passion and intensity. Given Natsu's sadistic nature, it can add an extra layer of heat and drama to their interactions. And in some fanfictions, there could be themes of redemption or transformation, where Natsu's sadistic side is either tamed or redirected in a positive way within the context of their relationship with Mira.
I'm not sure of specific Mira x Sadistic Natsu fanfictions offhand. You could try searching on popular fanfiction websites like Archive of Our Own. There might be a wide variety of stories there with different plotlines and interpretations of their relationship.
Another theme is the exploration of their pasts. Some fanfictions delve into their individual backstories and how those experiences shape their relationship. For example, how their childhoods or past traumas might affect how they interact with each other and grow closer. It gives a deeper understanding of their bond. This can also include things like family relationships and how those play into their connection.
One common theme is adventure. Since both Ash and Mira are often associated with exploring and discovery in the Pokemon world, fanfictions usually involve them going on some kind of exciting adventure together, like exploring a new region or uncovering a long - lost secret.
Common themes in fanfictions about Natsu and Mira from Fairy Tail include growth. Both characters can grow as individuals through their interactions. Natsu might become more mature in how he approaches problems, and Mira could become more confident in her abilities. The theme of family is also there, as the Fairy Tail guild is like a family. Natsu and Mira's relationship within this family - like environment can be explored, such as how they support each other during tough times in the guild or when dealing with personal issues.
Adventure is also a popular theme. They might embark on quests or explore new places together. Like in some fanfics, they travel to uncharted regions to find a lost artifact or solve a mystery. This allows for a lot of exciting plot developments.
One common theme is the clash of different cultures. Naruto comes from a world of ninjas with its own set of values and traditions, while Mira is from her own distinct world. So, there's often exploration of how they deal with these differences.
Friendship is a very common theme. Since they are both characters from the same universe, their friendship often forms the basis of many fanfics.
Friendship is a common theme. Since it's Natsu interacting with various characters, the fanfics often explore how different friendships form and develop. For example, his interactions with Lucy might be different from his interactions with Gray.
One common theme is the exploration of their different personalities coming together. Natsu is bold and impulsive while Aries is more reserved. Their interaction and how they balance each other out is often explored.
A prevalent theme is the power of teamwork. Given their different skill sets, they make a great team. Fanfictions will often highlight how they combine their powers to defeat enemies or solve problems. And of course, there's the theme of loyalty. They are loyal to their friends and comrades, and in the context of their relationship, this loyalty is often a key factor in strengthening their bond.