Actually, there IS a novel, Destiny Embers is literally a book made by Brad, Stardock's ceo.
http://www.amazon.com/Elemental-Destinys-Embers-Bradley-Wardell/dp/0345517865/ref=sr_1_1?ie=UTF8&qid=1372385397&sr=8-1&keywords=destiny+embers
This however is not the backstory as much as it is another tale set in the same world. It takes place in the year 1000 after the cataclysm, so the War of Magic and all of our sovereigns are just legends by then.
An actual backstory... There IS, the Hiergamenon is somewhere online, but I fail to recall where, it told the story of the Hosten and the other old famous people, the Cataclysm, and whatnot.
I will see if I can find that online lore book, but do consider checking Destiny Embers, while it is not lore centric, it is still a great story and does delve into some lore, and bits of it are not even mentioned in game.
