From the website:
Khalgun is a broken world. The Old Gods fought one another to mutual destruction, obliterating magic and swallowing much of the planet in a permanent Worldstorm. The Five Kingdoms that remain live by an uneasy truce born out of necessity, a peace which is tested when the New Gods begin to arise.
The Godsfall Worldbook was designed to work with the fifth edition of the greatest fantasy RPG game ever written. It contains an original and expansive fantasy story, maps, races, art, creatures, rules, NPCs and the super-human abilities that empower the gods known as divinities.
After a Kickstarter campaign that raised more than twice the original goal set for production, the Godsfall Worldbook is ready for pre-order.