Hm,
I know I am beating a dead horse, but I think the amount of egyptian vibe ( remember the Warcry and Forbidden Power trailers) and the fact that there is a yet unanounced faction for War Cry left, with Death as the only GA only having 2 warbands, point to a certain someone who DOES NOT SERVE.
It is also worth mentioning that Slaanesh's prison is right next to Shadespire, where once the Katophanes lived. These guys and their shadeglass could turn out to be the new construct death faction. Say what you will but this is hardly a "coincidence" anymore.
https://ageofsigmar.fandom.com/wiki/Slaanesh?file=Slaahesh_Imprisoned_between_Ulgu_and_Hysh.jpg