Banana Fish is not based on real events. It's a fictional narrative that takes the reader/viewer into a made-up world with its own unique plot and characters.
The ending of the Banana Fish anime aligns with a certain part of the manga. It's around a crucial juncture in the story, where major events unfold and character arcs reach important milestones.
Banana Fish is purely fictional. The plot, characters, and events were all imagined by the writer to create an engaging and unique narrative. There's no real-life inspiration behind it.
The best place to find 'banana fish fanfic' is definitely AO3. It not only has a vast number of fanfics but also a very active community. This means that new and updated fanfics are constantly being added. Additionally, the site allows for detailed tagging and categorization. For example, if you want to read a fanfic that focuses on the relationship between Ash and Eiji, you can easily find it by searching for the relevant tags. Some smaller, more niche fanfic communities might also have 'banana fish fanfic', but they can be harder to find.
Archive of Our Own (AO3) is a great place to start. It has a large collection of Banana Fish fanfics. Just use the search bar and type in 'Eiji kidnapped' or something similar. You might also check some other fanfic - specific websites or forums dedicated to Banana Fish, but AO3 usually has a wide variety.