Empire in Black and Gold (Shadows of the Apt Book 1) by Adrian Tchaikovsky (Kindle Edition)

The days of peace are over . . .

The Lowlands’ city states have lived in peace for decades, hailed as bastions of civilization. Yet that peace is about to end. A distant empire has been conquering neighbours with highly trained soldiers and sophisticated combat techniques. And the city states are its desirable new prize.

Only the ageing Stenwold Maker – spymaster, artificer and statesman – foresees the threat, as the empires’ armies march ever closer. So it falls upon his shoulders to open the eyes of the cities’ leaders. He sees that war will sweep through their lands, destroying everything in its path.