>>63696166>Demons of Emperor?
I'd say that the nature "daemons" in 40k are parallel to their patron deities in a number of ways.
The Emperor, along with being an actual god, also has a definitive physical body.
Therefore his "daemons" would reflect this nature, the primary example being the Saints, who are regular humans imbued with the power of the Emperor.
Chaos daemons on the other hand are pure warp entities, as such they must expend warp energy in order to maintain a physical form.
Considering all of this I wouldn't call the Legion of the Damned "Daemons of the Emperor".
The primary reason being that their warp affliction causes them to slowly lose their sanity and degrade at a cellular level, something the Living Saints obviously don't suffer from.
The LotD's special abilities probably come from a combination of mutation(they were a cursed founding chapter after all) and the destructive influence of the Warp.