Some fanfics interpret it as a curse. They might depict Eren as a tragic figure, burdened by this power he didn't ask for. His transformation could be seen as something that isolates him from his friends and loved ones, as they fear his Titan form.
I'm not sure who exactly Charles Falco is without more context. There could be many people named Charles Falco. Maybe he's a local figure in a specific community, an artist, or someone involved in a particular event.
One reason could be the raw power it represents. Eren's transformation into a Titan is a visually stunning moment in the series. In fanfics, authors can explore this transformation in more depth. They might describe the physical sensations Eren feels, like the rush of energy coursing through his body as his form changes. This adds a new layer of understanding to an already iconic moment in the anime.
I don't know for sure if it's a book. It could be a story told in other forms like an oral tradition, a digital story, or even a performance piece. There's not enough information to say it's a book.
I'm not entirely sure specifically about a 'falco never ending story'. It could be a very unique or personal creation. Maybe it's a story created by someone named Falco that has a continuous or open - ended plot. Without more context, it's hard to say more.
Love and friendship is a big theme as well. Their relationship can be seen as a deep friendship that has the potential to turn into love. Fanfics explore different aspects of this, from the awkward first moments of realizing there are deeper feelings, to the more mature and stable relationship they could have in the future.
One common theme is friendship. They are both characters from the Smash Bros. series, and many fanfics explore their relationship as comrades, like going on adventures together in the Smash universe.
One great Star Fox Falco and Katt fanfiction is 'Falco's New Adventure with Katt'. It's really engaging as it shows their relationship developing during a dangerous mission. The story has a lot of action and also some really sweet moments between them.
I'm not sure about specific popular 'Falco gay fanfic' stories as it depends on different fan communities. You could try searching on dedicated fanfic platforms or forums related to the character Falco to find such stories.