Hi guillepb! Welcome to the forum!
I love your story idea! There's plenty of scope for a game within it. One question I have for you, though, is how does the Eye move to the moon? It seems to require the power that is only available at the starport for it to be opened. I'm not sure the Eye could naturally move to the moon. However, other than that I like it, and such a small detail doesn't really affect the rest of the story anyway.
I'm interested in the names you used. As far as I know, there are no examples of Cocytan names anywhere? (Unless they are in the Strategy Guide, which, as I have said, I don't have. I'd love to see any particular examples included in the guide, if anyone can be bothered.)
I'd love to hear some ideas for a prequel. I suppose a prequel would not involve humans in any way. That would certainly be a challenging project, especially for an amateur.
PS Your English is better than some who call it their mother tongue!