This is really cool. It adds a new magic system (very simple and straightforward, nothing fiddly) to the game that is only available to chaos worshipping monsters. Along with those rules comes a list of spells that seem designed for making combat encounters more interesting. The whole thing is quite cleverly thought up and very flavorful. Though it is tied in with ME's campaign setting, it is general enough that anyone who includes dark chaos forces in their setting (who doesn't?) can use it with no adaption required. Really great stuff