Thats my Karanak conversion :)
Before the new codex, my Daemon list was built purely for fluff purposes. I was running pink horrors, flesh hounds and nurglings - none of which could be considered powerful units. OK I had Fateweaver in there too, but in most games he ended up being more of a hindrance than a boon and pissing off around turn 2.
A new codex comes around and of course everything changes. Fateweaver is now a shadow of his former greatness, and Horrors and Hounds are bloody brilliant. Admittedly I am playing primarily on a 4'x4' table where the Hounds can get to the enemy easily and the Horrors are usually in range of something. Still, they have been performing brilliantly even under my sub-par generalship.
I'll take you through my 750 point force and then show how I intend to build this up to 1500. Here's the little version:
Chaos Daemons (750)
Karanack (120)
Herald of Tzeentch - Psyker (mastery level 2), Exhalted Locus of Conjuration (95)
17 Horrors (153)
16 Flesh Hounds (256)
4 Nurglings (60)
4 Nurglings (60)
Flesh Hounds now have 2 wounds, which makes them amazingly resilient. OK so they don't have power weapons, but thats not always a bad thing. It means that the unit can remain in combat for the opponents shooting phase against Space Marines. And with S5 on the charge they easily rip holes in any kind of mech with rear armour 10. Oh wait they also have scout! Push them forward 12" after setup and you have one uncomfortable opponent :)
Karanak is a beast (as well as literally). Strength and Toughness 5, and he gives Rage AND Hatred to the flesh hounds. Combine that with the Furious Charge that all Khorne Daemons get and you have one unit that is terrifying on the charge!
Initially I was annoyed that the Horrors had lost their previous Assault 3 ranged attacks. But they have gained a lot in this new incarnation, whilst coming in at HALF the points cost. Using the default Tzeentch power, a unit of 16+ gets 4d6 S5 attacks at 24".
But that is not the full story, you have to add a Herald of Tzeentch to get that. He can bump those attacks up +1S and cast prescience on the unit so they can reroll hits and wounds. He also adds another 2d6 attacks to the units ranged attack, hitting on 3s. Sure you spend on points but I'm pretty sure its worth the pennies.
So last of all I have the poor Nurglings, who have picked up Shrouded but lost Eternal Warrior. Pretty much unchanged in effectiveness. I usually keep them in reserve, and deep strike them in to contest objectives, or tie up enemy shooting units. They work OK.
Chaos Daemons (1500)
Karanack (120)
Herald of Khorne - Greater Reward, Exalted Locus of Wrath, Juggernaut of Khorne (145)
Herald of Tzeentch - Psyker (mastery level 3), Exhalted Locus of Conjuration (120)
Herald of Tzeentch - Psyker (mastery level 3), Exhalted Locus of Conjuration (120)
20 Horrors (180)
20 Horrors (180)
16 Flesh Hounds (256)
16 Flesh Hounds (256)
4 Nurglings (60)
4 Nurglings (60)
So this is roughly how I imagine the list will scale to 1500 points. Two big units of Horrors blasting out S6 shots to anyone who comes near. Two big units of Flesh Hounds marching forward to threaten the enemy battleline. The Herald of Khorne is a poor mans Karanak, giving Hatred but not Rage. At least he brings some AP2 to the party.