Quote Originally Posted by Zezlar View Post
It is very much apart of the story. It's just a re-imagining of what happened when the player went to face Darnus. It just doesn't advance the story in any fashion over the current normal version. Doesn't mean it's not part of the Umbral storyline.
Primals have to do with the story as well. Thats why their easy mode is being removed and changed in the list of removed achievements. But hard mode wasnt enough apparently and the items involved with it are confirmed to be staying.