Empire of Rust — Val St. Crowe

Two hundred and fifty years ago, the world was overrun by the revenants: perfectly preserved dead things that feed on the living. The holy men claim this was a punishment on mankind for learning too much, for delving too far into technology. Now, only a privileged few even learn to read.

Enthralled with the past, Gabriel, son of the emperor, is seduced by a vision. Democracy, electricity, and freedom to indulge his attraction to men. How could the enlightenment of the past be as evil as the holy men claim?

But when Gabriel's father dies, Gabriel becomes the emperor overnight. He wants to bring knowledge and freedom to the people and defy the old scriptural laws. However, he doesn't count on his sister's marriage to a necromancer, a man who can control the revenants, who can lead a revenant army.

And he doesn't expect her and her powerful husband to challenge his throne.

Now it is down to war -- men against revenants, the living against the dead. And how can they win against such an army? The revenants do not feel their wounds. They never tire. They never sleep. And they are always hungry.