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 Levi x Mikasa fanfiction from Attack on Titan, a common theme is the exploration of their pasts. How their upbringings and past traumas have shaped them into the people they are and how that affects their relationship. Also, the theme of loyalty is big. They are both extremely loyal to their causes and to the people they care about, and fanfiction often delves into how this loyalty plays out between them. There is also the theme of them being the last hope in some scenarios, where they have to rely on each other to save humanity from the Titans.
In the 'Attack on Titan' series, there is no clearly defined canon romantic interest for Levi. His character is mainly focused on his role as a soldier and his fight against the Titans. However, many fans like to ship him with various characters in fan - made love stories.
Create a believable plot. Since it's set in the Attack on Titan universe, there should be elements related to the Titans, the military, and the overall struggle for survival. For example, the reader could be involved in a mission against the Titans, and that's where their relationship with Levi starts to develop.
A great 'Attack on Titan Levi Fanfic' usually has a deep understanding of Levi's character. For example, it should capture his stoicism, his loyalty, and his no - nonsense attitude. If it can show his growth or how he deals with his past, that's even better.