The Empireus had given life to the world with darts of the purest energy. Now It is about to end life in the same way.
At least this is the well-founded impression of the astonished mortals who dared to challenge It.
I am not against Age of Sigmar setting, I would just have preferred that Warhammer world did not broken in the end, it could have become an hellish battlefield where few Heroes fight in subterranean dungeons. Where finally Stormcast came from the storm to defeat the overwhelming forces of Chaos.
I prefer Stormcast as horsemen because of their heavy armour. They mount war-unicorns, a small link to Bretonnia.
Empireus means the firmament, the pantheon of the Gods, I would translate with Empyrean, but this word means Warp..! Maybe it's right Warp too...