One common theme could be the exploration of their relationship dynamics. It might involve how they interact, whether it's in a friendly way or with some underlying tension.
One common theme could be the exploration of complex relationships. Since yaoi often involves male - male relationships, there might be a focus on the emotional connection and the power dynamics between 'greed ler' and 'once ler'.
A 'ler light novel' is likely a specific type of light novel. Light novels are usually short, easy - to - read novels often with anime - like illustrations. However, without more context, it's hard to say exactly what makes a 'ler light novel' unique. It could potentially be a light novel related to a specific genre, series, or publisher named 'ler' or it could be a misnomer or something very niche.
I'm sorry, but I don't have specific 'greed ler x once ler yaoi fanfiction' to recommend directly. You can try searching on some popular fanfiction websites like Archive of Our Own. There might be a wide range of works in that genre if they exist within the site's guidelines.
I'm not sure about specific 'once ler x greed ler fanfic' off the top of my head. You could try searching on popular fanfic websites like Archive of Our Own. They usually have a wide variety of fanfictions in different categories.