I'm not familiar with the specific main characters in '86 volume 2 light novel'. But in general, light novels tend to have protagonists who are often young, with unique personalities and abilities. They could be fighters, strategists, or people with special powers. In a volume 2, the main characters might be the ones who were set up in volume 1 to face new challenges. It's also possible that there are secondary characters from volume 1 that step up to become more central in this volume, depending on the direction of the story.
Since I haven't read '86 volume 2 light novel', I can't give you the exact main characters. However, in many light novel series, the main characters are often the ones who drive the story forward. They are likely to be the ones with the most complex backstories, goals, and relationships. Maybe in this volume, some new characters are introduced who become main characters or the existing ones from volume 1 have their roles expanded.