"The setting is set on the world of Scarn in a post-apocalyptic era where the world is recovering from a horrific war between the Gods and Titans, which ended 150 years ago and left the land warped.
In need of a way to rid the world of the whimsical and dangerous titans, the gods - the children of the titans - decided to unite against their parents. However, the essence of the titans are inseparably bound to the world of Scarn, since they are the world's creators, and so the gods are obliged to simply incapacitate their parents instead of destroying them. Hacked to pieces and/or chained, the felled titans are a constant incentive for the titan-worshippers to resurrect their masters and for the divine races to continue fighting against the titanic abominations.
A great deal of the system's appeal comes from the detail of cultures, cities, governments and history given by the module books. There are also several continents which have been influenced in a lesser degree by the Titan/God war.
Source: Wikipedia, "Scarred_Lands", available under the CC-BY-SA License.