The 'Jungle Juice Light Novel' might be about a variety of things. It could be centered around a jungle - themed adventure where the characters encounter strange creatures and face various challenges. Maybe there are also themes of power and growth as the characters develop their skills or abilities within the story. It could also involve complex relationships between different characters.
Jungle Juice fanfic is often based on the 'Jungle Juice' series. It typically involves fans creating their own stories within the world and characters of Jungle Juice. These stories can range from adventure - themed ones, exploring new aspects of the Jungle Juice universe, to character - centric tales that focus on the development and relationships of the characters in the series.
Not having read the 'Jungle Juice Light Novel', it's difficult to say who the main characters are. But generally in light novels, there are characters that are central to the plot. There could be a young and determined character at the heart of the story, with friends or allies who join them on their adventures. There might also be a powerful enemy or rival that the main character has to face off against, all of which contribute to the development of the story.
You can try searching on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, and there's a good chance you'll find Jungle Juice fanfic there. Another option could be FanFiction.net, which also hosts a wide range of fan - created stories.