Another common theme is the search for identity. In a crossover, the lancer of red may question who they are in this new context. Are they still the same character with the same values? This internal struggle can be a central part of many 'lancer of red crossover fanfiction' stories.
Well, Archive of Our Own (AO3) is also a great place. There might be some really creative 'lancer of red crossover fanfiction' there. Some authors might combine the character with other popular universes, creating unique storylines.
I'm not entirely sure as I haven't played it myself, but generally in a game or story named Star Lancer Story, it might involve space battles, exploration of different star systems, and the adventures of the characters who are likely starship pilots or something similar.
One unique feature is the blend of different concepts. The Lancer archetype, often from other fictional universes, is combined with the rich world of Naruto. For example, the combat styles can be very different from traditional Naruto combat, bringing in new and exciting fight scenes.
Yes, there are some out there. However, 'lemon' usually implies mature or inappropriate content in fanfiction. It's better to look for more general, non - explicit fanfictions about Saber and Lancer which can focus on their relationship, battles, or character development.
I'm not sure if it's a popular genre. It might be popular among a very niche group of fans who are interested in the character of Johnny Lancer and the concept of exploring abuse in relation to that character, but it's not likely to be a mainstream or widely popular genre.