Skarbrand

For some reason, I really like Skarbrand. He's a cheap flightless bloodthirster that causes hatred and rage in ALL units within 12". That means if you want to get use out of him you need units that charge 1st and go 1st in close combat. I really don't know how you would do this. Slaanesh daemons is just more wrong than usual. Really big units of chaos space marines with mark of slaanesh in Storm Eagle or Spartan? Lots of little units of slaneesh chaos space marines with champions jumping out of dreadclaws and landraiders?
Anyway it's not very khorne-y. You could go for unmarked spacemarines and mutually assured destruction...
Possessed landraider with dirgecaster seems like throwing good points after bad.
 I had thought dark eldar but apparently they are just as scared of chaos as orks and necrons...

Anyway, getting the bloodthirster on the table at 500 points..

Bloodthirster 250
Bloodletters x10 100
Bloodletters x15 150

or

Skarbrand 225
Daemonettes 90
Sorcerer 60
Cultists 50
Chaos Marines 75

or

no skarbrand, but 2 daemonprinces under 500 points lololol

Daemon Prince (slaanesh) 155
Daemon Prince (slaanesh) 155
Daemonettes 90 with instrument of chaos 10
Daemonettes 90

Allies is a bit hard at 500 points, so at 1000

Skarbrand
Daemonettes