The Mercy of Gods (The Captive's War, 1) by James S. A. Corey

From the New York Times bestselling author of the Expanse comes a spectacular new space opera that sees humanity fighting for its survival in a war as old as the universe itself.

"The start of something truly epic."  ― Fonda Lee, author of Jade City

How humanity came to the planet called Anjiin is lost in the fog of history, but that history is about to end.

The Carryx – part empire, part hive – have waged wars of conquest for centuries, destroying or enslaving species across the galaxy.  Now, they are facing a great and deathless enemy. The key to their survival may rest with the humans of Anjiin.  

Caught up in academic intrigue and affairs of the heart, Dafyd Alkhor is pleased just to be an assistant to a brilliant scientist and his celebrated research team.  Then the Carryx ships descend, decimating the human population and taking the best and brightest of Anjiin society away to serve on the Carryx homeworld, and Dafyd is swept along with them.

They are dropped in the middle of a struggle they barely understand, set in a competition against the other captive species with extinction as the price of failure.  Only Dafyd and a handful of his companions see past the Darwinian contest to the deeper game that they must play to survive: learning to understand – and manipulate – the Carryx themselves.

With a noble but suicidal human rebellion on one hand and strange and murderous enemies on the other, the team pays a terrible price to become the trusted servants of their new rulers.

Dafyd Alkhor is a simple man swept up in events that are beyond his control and more vast than his imagination.  He will become the champion of humanity and its betrayer, the most hated man in history and the guardian of his people.

This is where his story begins.

"Corey is always one of the most engaging voices in the genre."  ― Adrian Tchaikovsky, author of Children of Time

"A bang up read. I want more."  ― Paolo Bacigalupi, author of The Water Knife

"A powerful, provocative masterpiece that I will be thinking about for a very long time."  ― Ryka Aoki, author of Light from Uncommon Stars