It's the contrast in their personalities. Garry is often more protective and worldly - wise compared to Ib's more innocent and curious nature. This contrast makes for interesting interactions and storylines in the fanfics.
Sure. One popular 'garry x ib fanfic' might be 'The Unseen Bond'. It delves deep into the relationship between Garry and Ib, exploring their shared experiences in the strange art gallery world. It has great character development and an engaging plot that keeps readers hooked.
Not likely. Usually, movies or shows labeled as 'IB71' are works of imagination. They might draw inspiration from various sources but aren't direct retellings of true stories. There could be elements that feel realistic, but that doesn't mean it's based on actual events.
I don't think it's purely based on a true story. Usually, in such cases, the filmmakers take creative liberties and mold the story to make it more engaging for the audience.