"Darksiders: The Abomination Vault", a new novel set a millennia before the events of the first game, will be released on the same day as Darksiders 2, THQ have confirmed.

In Darksiders: The Abomination Vault, the Horsemen of the Apocalypse have uncovered a plot to resurrect ancient weapons of unimaginable power. Death, with the help of his compatriot War, must track down and neutralize the mysterious individuals behind the scheme before the entire universe is plunged into a devastating conflict.
Random House Worlds, the Random House Publishing Group's intellectual property creation and development group, will also develop the IP bible for the Darksiders universe.
Joe Madureira, creative director of Darksiders and it's sequel has previously expressed a desire to work on a Legend of Zelda comic book.
Darksiders 2 is currently set for release in Q2 2012. Let's hope that's next on the list.