Reaper by Will Wight

Sacred Valley has been saved…at least, what’s left of it.

With his home finally secure, Lindon delves deep into the ancient labyrinth, seeking long-lost Soulsmithing knowledge and the secret to destroying the Dreadgods. Monarchs plot against him and against each other, unaware of the threats gathering in realms beyond.
Far above Lindon and the Monarchs and the Dreadgods, another war is waged. Suriel and the Abidan clash against the Mad King and his forces in a battle for the fate of many worlds.
And if it is lost, Cradle will be destroyed