Friendship is also a theme that often shows up. The male reader might start as Mikasa's friend and then the relationship could develop into something more. Redemption is another one. Maybe the male reader has a past mistake and through his relationship with Mikasa, he finds a way to redeem himself. Also, the theme of survival in the harsh world of Attack on Titan is quite common in these fanfictions.
A theme of family and loyalty often emerges as well. Since Mikasa has a strong sense of loyalty to her friends and comrades in the original series, this can be extended to her relationship with the male reader. They might become like family to each other, and the fanfiction could explore how that bond deepens over time and through various challenges.
One common theme is adventure. Since the world of Attack on Titan is full of danger, many fanfictions will have the male reader and Mikasa going on dangerous missions together. Another theme is loyalty. Mikasa is very loyal in the original story, and this trait often carries over into the fanfictions, with her being loyal to the male reader as well.
One common theme is protection. Mikasa is a strong character, and in many fanfictions, she is shown protecting the reader from various threats. For example, in fictions set during battles or dangerous situations.
Another theme is mutual support. Given Mikasa's strong and protective nature, she might be shown as a source of support for the female reader in difficult situations, and vice versa. For example, when the female reader is dealing with the loss of a loved one, Mikasa is there to comfort her, and when Mikasa is having doubts about her own actions, the reader offers words of wisdom.
One common theme is role reversal. Since Mikasa is often portrayed as a strong, protective figure in the original, making Mikasa male in these fanfictions often emphasizes that role even more towards female Eren. Another theme is the exploration of different gender dynamics. For example, how a male Mikasa might court or show affection to female Eren in ways different from the original dynamic.
One common theme is friendship. The oc often starts as a stranger to Mikasa and they gradually become friends, sharing their secrets and fears. For example, in many fics, they bond over their experiences with Titans.
Friendship is a common theme. Since they are comrades, many fanfictions explore how their friendship could develop into something more. For example, they might start to rely on each other in different ways than just as fellow soldiers.
In Naruto x Mikasa Ackermann fanfiction, a frequently seen theme is the adaptation to a new world. For example, if Mikasa somehow ends up in Naruto's world or vice versa, how they adapt to the different rules, cultures, and people. Another theme is the combination of their combat skills. Writers might explore how Naruto's Rasengan could be used in conjunction with Mikasa's acrobatic fighting style. And there's also the theme of understanding different value systems. Naruto values friendship and the will of fire, while Mikasa values protecting her loved ones. How they come to understand and maybe even adopt some of each other's values is often explored.
One common theme is adventure. Since Renamon is from the Digimon world, many stories involve the male reader going on adventures with her, battling other Digimon and exploring new areas. Another theme is friendship that develops into something more. At first, they might be just friends, but as the story progresses, romantic feelings start to emerge.
A recurring theme is the male reader helping Arcee overcome some sort of emotional trauma. Maybe she lost a friend in battle and the reader is there to support her. There's also the theme of discovery, where the male reader discovers the secrets of the Transformers world through his relationship with Arcee. This can include learning about their technology and their history.