Durotan takes place in what I guess was meant to be the Warcraft cinematic universe rather than the game universe. It somewhat retells events covered in Rise of the Horde, but is focused solely on the Frostwolf clan. Doomhammer is now in the Frostwolf clan rather than the Blackrock clan so we can have a recognizable name as Durotan's lieutenant. It's a solid story, but I feel it would have been better without any reference to Warcraft at all. Random Orc Tribe novel wouldn't have the baggage of a story that has already been told by the same author.