Grave Empire is the novel that kickstarts the epic fantasy series The Great Silence, written by Richard Swan and published by Orbit Book. Set in the same world as The Empire of the Wolf, but centuries later, in a Sovan Empire where magic has been outlawed, an ancient prophecy heralds the end of days; on the brink of collapse, we will be following three characters that each one will have their lives changed by the recent events.

The first of our three POV is Renata Rainier, assistant to the ambassador to the mermen; a position that is not taken seriously by her colleagues (Swan makes it clear from the very first chapter), but that will have to step up when two monks arrive at the capital bringing an ancient prophecy. She will finally get to know the mermen, but in the current situation in the empire, her journey will be plagued by difficulties, even some supernatural ones; and honestly, exploring the culture of the mermen through the lense of somebody that only knew them theoretically is an excellent exercise. With Renata, we have a character that grows against adversity, with a big responsibility over her shoulders.
In the second of our POV, we have Peter, a soldier sent to the frontier; Swan doesn't give a single break to the poor boy, showing the dangers of those lands and the creatures that inhabit there. During his chapters, horror takes over fantasy, keeping you constantly in tension, wondering if this will be the last chapter you read from the poor Peter's perspective.
And finally, with von Oldenburg's POV, we have an ambitious lord of the Empire, one that is not afraid to cross the lines in his search for power; and while there are people at his side that tried to stop him, we will see how his greed and power crave takes over him, trespassing many limits in his endeavour.

The three POV are masterfully woven together to create a vibrant and epic story that takes us to many places in the Empire, gradually exploring more locations and presenting us to other inhabitants of this world such as the mermen and the wolfmen, all with fully fleshed cultures and lifestyles; we can appreciate that it is still the same world as in the previous trilogy, but how it has changed as time has passed bringing progress with it. 
While the pacing can be a bit slow at the start, as Swan is introducing to the changes Sova has experienced, it fastly picks up, inviting you to devour this book in a few sits because you know how this continues.

Grave Empire is simply an excellent novel, laying the foundations to another epic story; a deeper worldbuilding (with some touches that remembered me to the Age of Madness trilogy) and a set of characters that each one will have to confront their own horrors to create something exquisite. I need to know how the Great Silence continues in the following books, but for one, do yourself a favour and read this book.