Indelible. Arrow of Time Chronicles, #3

Tori Bertoletti, librarian and planet cataloger, and Raze Salen, mankind's emissary, aboard the Human spacefaring liveship the Aero have succeeded in creating a Galactic Alliance with other cultures in their universe in order to protect themselves from an adversary who considers itself the supreme race, the Chosen of the Creator. Cultures that at one time would have considered all others antithetical to their own no longer have a choice about facing the indisputable fact that, though they've all come from different planets and far-flung sectors of the galaxy, they are genetically one and the same.
But can the enemy of my enemy become my friend against the warring Sinshe...as well as an organic process that won't be stopped until all life to the farthest corners of the universe ceases to exist and only darkness reigns?