Warhammer 40K Tabletop XIX: "Understand the gravity of the situation."

[deuterio12]

Night Lords. Raptors as Troops, terror tactics (Fear everywhere, infantry packing Dirge Caster equivalents, that sort of thing), lots of speed for the army. No Cult Troops, but maybe slightly better generic CSM and Raptors to make up for it.

No, I'm not just saying that because my own CSM fight like Night Lords all the time.

The Horus Heresy:Massacre book has rules for the Night Lords legion. Fear everywhere, have a chance to force Night Fighting, and an elite CSM squad with infiltrate that can be taken as troops (they also have super-raptors, but fast attack only). Best of all is that Fear actually does something in WH 30K, since ATSKNF doesn't exist (most power armor dudes just have "can regroup if below 50% starting size", with some stubborns here and there and then a few Fearless units).