The 'oathbreaker novel' may explore different aspects. It could be a story set in a fantasy realm where oaths are magically binding. The main character, an oathbreaker, might be shunned by society or hunted down. Or perhaps it's a story about a person who breaks an oath for a greater good, but still has to face the internal and external consequences. It could also look at how different cultures within the novel's world view oath - breaking, whether it's an unforgivable sin or a necessary evil in certain situations.
I don't know the exact main characters as I haven't read the 'oathbreaker novel'. But it's likely to have characters directly involved in the act of oath - breaking, like the oathbreaker themselves, and those who are affected by it, such as their friends, family or enemies.
I'm not entirely sure as I haven't fully explored it myself, but generally a visual novel is a form of interactive story. 'Oathbreaker' might be about a story where someone breaks an oath, perhaps in a fictional world filled with different characters and relationships.
I don't know specifically since I haven't played or studied this visual novel in depth. But usually in a story about oath - breaking, there could be the character who breaks the oath, someone who is affected by the broken oath, and perhaps a mentor - like figure who tries to guide the oath - breaker.
There could be BH 90210 fanfics that explore relationships that were only hinted at in the show. Maybe a story about two characters who could have been a couple but never really got the chance in the actual series. Fanfics give writers the freedom to develop such relationships in more depth, with different plot twists and character growth.
One interesting aspect could be the exploration of alternate character arcs. For example, characters might break their oaths and have to face the consequences, which can lead to a whole new set of relationships and story developments. It might also delve into darker themes that the original series only hinted at, like the true cost of power and loyalty.
The theme of sacrifice is also present. In some 'bh love stories', one person may sacrifice their own dreams or opportunities for the sake of their loved one. For instance, a person in BH gives up a job opportunity in a big city to stay with their partner who has a family - related obligation in BH.
One interesting 'bh90210 fanfic' story could be about the characters going on a road trip together. They might face various challenges along the way and in the process, their relationships deepen. For example, two characters who were initially at odds start to understand each other better.
You can try some fanfiction websites like Archive of Our Own (AO3). It has a large collection of fan - created works including BH6 fanfiction. Just search for 'Big Hero 6 fanfiction' on the site and you'll likely find many stories to read.