SOLVED. Book about a 3-way war between beasts, machines, and humans. [s]

[Jack]

I believe there were 2 protagonists in alternating and eventually colliding plots. The girl (and maybe the boy as well) somehow had genes from the other 2 species and was able to interact with them and control(?) them. Something about a floating city, underground (mine?), and at the end a destructive force was released on the world by the girl protagonist. All of this is really vague so expect some inaccurate information, but I think most of it is correct. Thanks

[Kris]

The Sky Village by Chris Rettstatt seems to match your description.

Jack, around what year did you read this book?
Is it part of a series? Young adult?

[Jack]

The Sky Village was exactly it! Thanks so much!

[Jack]

That was it thanks a lot!

[Kris]

Great! Glad you found your book. :)