This is a proof-of-concept list I've been testing out over the past few weeks. It's...amusing I find. It's based on LVO-like restrictions ("Two detachments max, no more than one CAD"), and modified Maelstrom (objective-grabbing and all that jazz).
=Mephrit Dynasty Cohort [Primary]==
=HQ=
[Warlord] Overlord on Catacomb Command Barge w/ Edge of Eternity, Phylactery, Phase Shifter, Gauntlet of the Conflagrator: 225
=Troops=
5 Immortals w/ Gauss - 85
-Nightscythe - 130
5 Immortals w/ Gauss - 85
-Nightscythe - 130
5 Immortals w/ Gauss - 85
=Elites=
5 Flayed Ones - 65
=Fast Attack=
Heavy Destroyer - 50
Heavy Destroyer - 50
Heavy Destroyer - 50
=Heavy Support=
Heavy Destroyer - 50
Heavy Destroyer - 50
Heavy Destroyer - 50
=Fortification=
Imperial Bastion w/ Comms Relay - 95
==CAD==
=HQ=
Sorcerer w/ Force Staff, ML 2, Spell Familiar - 100
Sorcerer w/ Force Staff, ML 2, Spell Familiar - 100
=Troops=
10 Cultists - 50
10 Cultists - 50
=Elites=
1 Mutilator w/ Mark of Nurgle - 61
1 Mutilator w/ Mark of Nurgle - 61
=Heavy Support=
1 Obliterator w/ Mark of Nurgle - 76
1 Obliterator w/ Mark of Nurgle - 76
1 Obliterator w/ Mark of Nurgle - 76
Total: 1850
Game Plan:
The unit of Crons without the Nightscythe gets to man the Each cult squad gets one Sorcerer; they deploy on separate flanks and roll Daemonology. Getting Cursed Earth is always a nice prospect, as is just being able to summon Daemonettes [I'm converting them up from what is sadly left of my olde 3rd ed Dark eldar minis; army transport is a sad affair] or Flesh Hounds (spare warhounds I had lying around). Most everything else has the option to either start in reserve, or on-table as needed. I took the Flayed Ones instead of a 3rd Mutilator because I like the idea of having some extra horde control, and because a spare unit of Infiltrators has its tactical uses (tag-team with an infiltrating Bargelord and some Immortals, and...).
I see its main weakness potentially being that most of its shooting is of the high-strength single-shot type; I "can" get assault cannons on my terminators for a turn, and I do have Nightscythes, but most of the shooting is of the heavy AT variety. I can get a turn or two if I sacrifice summoned dudes, or a cultist blob, but improperly screened, the army will collapse. The melee capacity of this list is "enough" to deal with mop-up more than anything else, and to disrupt parking lots.