The community is also a great place to check out. Try these places for help from other users:
You do not need to do anything. The DLC will be added to your account when it is available.
Redeem your code at http://community.darksiders.com/tomb
First, please ensure that you are not attempting to activate an Argul's Tomb CD Key in the format 1A2B-C34D-E5F6. Steam CD Keys for this game are 15 characters long in the format 1A2BC-34DE5-F6G78. See above for information.
Next, please ensure that you are attempting to activate the CD Key for the game and not Downloadable Content (DLC). You must activate the game before activating DLC. Each CD Key should be clearly labeled as to what it activates.
For further issues, please see the Invalid CD Key article for more information.
If you believe you are missing DLC, please ensure that you have activated all CD Keys that came with your preorder, retail, and/or digital retail product.
You must log into your THQ account when prompted in-game in order to access the Van der Schmash and Mace Maximus DLC items. Once you have linked your account, please visit the following locations:
If you're encountering issues with launching Darksiders 2, make sure everything installed smoothly.
Exit Steam entirely.
Browse to your Darksiders 2 installation folder (Usually C:\Program Files\Steam\steamapps\common\Darksiders 2\)
Run the following installers:
Reboot your computer and test any issues again.
If the above does not resolve the issue and you are running Windows 7 or Windows Vista, please complete the instructions in our Windows 7 and Vista Troubleshooting FAQ.
If you are running in Windows XP, take the following steps: