I'm not sure specifically as there could be various interpretations. It might be about human distrust ('ningen fushin' can be related to lack of trust in people) in a fictional context, perhaps exploring relationships and the consequences of such lack of trust within the story.
I'm not entirely sure as it could be a rather niche or new series. It might be about some unique characters or a particular world created by the author. Without more information, it's hard to say specifically.
One idea could be a crossover with the Dragon Ball Super universe and the DC Comics universe. Zamasu could team up with Darkseid, believing they share a similar view of bringing 'order' to their respective realms. Another idea is a crossover with the Naruto universe, where Zamasu tries to impose his will on the ninja world, facing off against powerful shinobi like Naruto and Sasuke. Or perhaps a crossover with the Star Wars universe, with Zamasu as a Sith - like figure, trying to gain control over the Force.
As I haven't read the 'ningen fushin novel', it's difficult to name the main characters. But generally in a story about such a concept, there could be a protagonist who is deeply affected by the ningen fushin around them. There might also be supporting characters like friends or family members who either contribute to the distrust or try to help the protagonist break free from it.
I'm not entirely sure as I haven't read it in detail. But generally, a light novel often contains elements like unique characters, a fictional world, and an interesting plot. It might be about the adventures, relationships, or struggles of its characters in a particular setting.
One interesting Zamasu fanfic could be about his origin story in more detail. It might explore his early days in the Kaioshin realm, his training, and how his ideology started to form.
Zamasu meets his end in the manga because he underestimates the strength and strategy of Goku and Vegeta. They exploit his weaknesses and deliver the final blow that finishes him off.
The 'ningen fushin no bouken light novel' could center around the journey of its protagonists. It may tell a story of how they overcome obstacles, both internal and external. Maybe it's about a group of people who, in their quest, discover new things about themselves and the world they live in. It could also have elements of different cultures or mythologies, which are often incorporated into light novels to make the story more engaging. Since it's a light novel, it's likely to be written in a style that's easy to read and understand, with a focus on the plot and the characters' emotions.