I think there's some parts of the story, especiaIIy one last story arcs, are pretty unique but of course I can't talk much about them without spoiling anything x'D
A, sadly, less important but unique factor in FIVE is this fella
That shadowy, feral, "inmortal" being is a character I'd love to do a separate mini comic or something about. They've been on Earth since almost the beginning of humanity and have been tied to one human and then other, and other and other. They're responsible for many of the differences between our Earth and FIVE's (for example there's monuments dedicated to them in several ruins and thanks to them Esperanto is spoken in most countries as an official second language).
Shia (the girl) and them go on trips to just spend some time away from civilization and survive just with what they can get from nature or, in other ocassions, go visit some ruins in places Sokar (the shadow) used to live c:
If there's something I'm confident to say my story is unique for it's the characters tbh x'D I could write a book about any of them.