Solid, unique, and compelling
I really enjoyed reading this story as far as I did while on a flight back home. You have a knack for presenting the world in a way that doesn't feel like you're leaving details out, but also offering a sort "in the know" feeling; that is me saying this as a person who's only read this story (though I will likely read the others now!). The characters feel very real, and Sirus in the preface was a stellar character to read. Celeste's personality is very well drafted within the first two chapters with her, and I feel overall that characters are your strongest element.
Read the story now
The only critique I'd have is the fact you have the preface split into four. I understand why, however a preface should be limited to a singular arc that sets up the story, frankly speaking, have bits of the first three prefaces and make it the fourth would've sufficed. But, I can tell that would've been against your wishes. So, consider the preface as your first arc of the story. My other distaste was the sudden double sex scene. I don't hate it, but it was a bit much for being right off the bat.
Seriously enjoyed it, and I hope to read more!