One common theme is her leadership skills. Since Levi is known for being an excellent leader in the original 'Attack on Titan', in fanfictions with a female version of him, this aspect is often explored further. Another theme could be her relationships, whether it's with other members of the Survey Corps or with new characters created by the fanfiction writer.
In Attack on Titan fanfiction, the relationship between Female Eren and Levi can be quite complex. Some fanfictions might explore a mentorship - like relationship, where Levi guides Female Eren in her growth as a soldier. He could be teaching her combat skills and how to survive in the harsh world they live in. This relationship might also be filled with mutual respect, as they both are strong - willed characters.
There's also 'Levi's Redemption'. This fanfic focuses on Levi's past traumas and how he overcomes them. The author does an amazing job of portraying his complex personality and his relationships with other characters in a very believable way. It's a must - read for any Levi fan.
In a Levi love story within Attack on Titan, Levi is often seen as a complex and stoic character. His love, if there was one, would be filled with his typical no - nonsense attitude. He might show his love through protecting someone in his own gruff way, like how he protects his comrades in the Survey Corps.
In Attack on Titan fanfiction, Levi and Mikasa's relationship can be quite interesting. They are both strong and skilled fighters. Their relationship might start from mutual respect for each other's abilities. Levi could see Mikasa's determination and be reminded of his own. Mikasa, on the other hand, might look up to Levi as a more experienced and powerful comrade. In some fanfictions, their relationship could develop into a deep friendship or even a romantic one, with them relying on each other in the face of the Titans and the complex politics within the walls.
One popular theme is the growth of their relationship. Starting from distrust or indifference and evolving into a deep friendship or something more. Another theme could be them facing challenges together, like a particularly difficult Titan attack where their combined skills are put to the test. Also, the theme of sacrifice might be present, where one is willing to sacrifice for the other in a life - or - death situation.