Lord Phostrin of the Sky Shoals, a Tzeentchian warlord, has grown tired of being manipulated by sorcerers. Now he seeks to climb out from under their sway with a magical gem possessed by Kairos Fateweaver that has the power to grant great power and immortality to its bearer. He has only to find it and claim it to achieve his destiny. Read it because It's a fascinating look at the lengths to which the servants of the Dark Gods will go in order to stand against the assault of the God-King's armies. It's a strongly character-driven piece – and with Guy Haley's flair for characters, you're in for a treat.
This book is part of the Warhammer: Age of Sigmar Books series and is book #8 in the series.