One interesting crossover could be the sharing of combat skills. For example, the pilots in Darling in the Franxx might learn some of the ninja techniques from Naruto characters. They could incorporate things like shadow clones into their battle strategies, which would add a whole new dynamic to their fights against the Klaxosaurs.
The main themes in 'Darling in the Franxx' include self - worth. The characters struggle with their place in society and how they are valued. Also, friendship and loyalty play a big part as the characters fight together and rely on each other. And of course, the theme of growing up and maturing is quite prominent as they face various challenges.
The anime 'Darling in the Franxx' is not for all ages. It delves into themes like self - discovery, relationships, and there are also some action - packed and intense mecha fight scenes. Additionally, the way the characters' relationships develop, especially the romantic aspects, makes it more suitable for an older audience, say, teenagers and above.
A common interesting plot point is the power exchange. For example, when characters from Darling in Franxx gain some of Naruto's chakra - based powers. It makes for really exciting battle scenes as they use these new powers in their own mech - combat style.
One great 'Naruto and Darling in Franxx fanfic' could be those that focus on crossovers of the characters' unique abilities. For example, a fic where Naruto's ninjutsu is combined with the mech - piloting skills in Darling in Franxx. It creates really interesting scenarios.