Some people just want to see the world burn. All those stuck-up, self-righteous, do-gooders make them sick. They'd much rather everyone run around, doing what they want. That's the sort of setting you're dropped into in Book of Exalted Darkness. It's a holy decopunk campaign world that you're looking to corrupt and destroy by whatever means you think'll work best. The book is written to be used with 5th Edition. It's also up on Kickstarter now.