From the little I have garnered about both practicing Luciferians and the all-mighty Illuminati both terms are obviously misnomers.
Luciferians, the dark ones at least, do not bring light - as the word Lucifer implies in its etymology - and instead promote their own toxic creed of obscurantism.
Ditto the illuminati, if the claims about them are true, are pretty fucking far from being as enlightened as their name would suggest. Rather in their manipulating and seeking to control others they would appear to be at the lowest possible level of human consciousness.
So, in light of this, let us rename Luciferians 'Light Concealers' and the Illuminati the Obscuranti (the Unenlightened Ones).