For anyone who didn't see, and considering there's no thread nor post on the front page for it, Blizzard published an interesting read on the inspiration for each fight, along with their concept of how their mechanics would work and what they would be, and some smaller background lore that isn't included in the Dungeon Journal.

I thought there might be a clue in Ra'den's section for what some of his abilities are, but none at all .

Enjoy the read though!