Well, without having read 'Trinity the Novel', it's hard to say precisely. However, if we consider the word 'trinity', it often implies a group of three. So perhaps the novel focuses on three main storylines that are connected in some way. Maybe it's three generations of a family, or three friends on different life journeys that ultimately converge. It could also deal with three aspects of a single character's personality.
The 'the trinity novel' could be about all sorts of things. It might be a story of three friends who are like a trinity, inseparable and each having their own unique role. Or perhaps it's about a trinity of secrets that the main character has to uncover. Maybe it's set in a post - apocalyptic world where there are three different factions, and the story follows the struggle between them which is symbolically presented as a trinity of powers.
Perhaps the fanfiction focuses on the cultural clash between the two groups. The Persona 4 characters are from a small town, while the Persona 5 crew is from the big city. Their different ways of handling things and their unique Personas could lead to some interesting interactions. For example, Yu and Joker might have different leadership styles that they have to reconcile in order to succeed against the shadows.
The 'holy trinity of science fiction' often refers to three key elements that are fundamental in many science fiction works. These could be things like advanced technology, alien life forms, and new social or political systems. However, different people might define it slightly differently depending on their perspectives in the vast realm of science fiction.
Since I haven't read 'Trinity the Novel', I can't tell you for sure who the main characters are. However, based on the title, we can assume that there might be three main characters. They could be of different genders, ages, or backgrounds. For example, it could be an old man, a young woman, and a middle - aged man. Or perhaps they are all from different social classes, like a rich entrepreneur, a poor artist, and a middle - class teacher. The relationships between these characters would likely be complex and form the core of the story.
I don't know as I haven't read it. But it could be three main characters given the 'trinity' in the title, like a hero, a villain and a neutral figure.
As of now, the DC Comics Trinity isn't being cancelled. Usually, such major decisions are accompanied by clear statements from the comic publishers, and there haven't been any such indications.