I loved Stephen R Donaldson’s The Chronicles of Thomas Covenant series of fantasy novels as a teenager. As a nominal adult, I find that they still hold up, including the final tetralogy. Outside of the writing style, theme, and narrative, one thing that struck me about the books was Donaldson’s glossary, as well as the synopsis of the previous novels. Not that the inclusion of either of those things was at all revolutionary, but they were helpful.
In that vein, I’ve added a page to the site under the Free Stories menu titled The Armageddon Series Character List and Glossary. It’s got definitions from Azazel the Watcher to the Higher Plane of Yesod, and everything relevant in between.