For a squad of chaos raptors, an icon of Khorne seems optimal from a previous analysis (see: parts I and II).
However, in recent times, the advent of dark eldar has got me re-thinking this conclusion. Lots more players are taking dark eldar (and there's still the die-hard eldar fans ... much like I'm a die-hard chaos marine and daemons player - kindred spirits). So, should I reconsider the Icon of Khorne?
I'll resurrect the three options that I was toying with originally: the raptor champion armed with a power fist, twin lightning claws, or simple baseline raptors. I'll put them up against ten dark eldar cabalite warriors instead of the usual space marines).
Let's look at each Icons in turn, and assuming that the raptors get the charge in.
With a Khorne Icon, the raptors gain an extra attack each, but they strike second.
Khorne Case 1: Baseline Raptors.
The kabalite warriors need 4+ to hit and 5+ to wound from 9 attacks. This results in 1.5 wounds, of which, 0.5 stick. The sybarite has a power weapon with 2 attacks. S/He also hits on 4+ and wounds (without a save) on 5+. That results in 0.33 more wounds, making 0.83 total.
The raptors hit on 4+ and wound on 3+ from 41 "normal" attacks (total) if everyone was still alive. Let's assume one is dead from the dark eldar. That means there are (only!) 37 attacks. That gives 8.22 wounds. (i.e. dW = 7.39).
Khorne Case 2: Power Fist.
Again, 0.83 wounds incoming from the first-striking dark eldar kabalite warriors. Assuming that one of the regular raptors perished, they get 8x4 attacks on the charge that results in a total of 7.11 wounds. The aspiring raptor champion gets 4 attacks (2 base, 1 charging, 1 from the icon), of which 2 hit and 1.67 kill. This gives 8.78 wounds (and dW = 7.95).
Khorne Case 3: Lightning Claws.
As above, but the champion has 5 attacks and 2.5 hit. They wound on 3+ with a re-roll for failed wounding rolls. This gives 2.22 more wounds for a total of 9.33 (and dW = 8.5).
For a Slaaneshi Icon, the chaos raptors strike simultaneously with the dark eldar.
Slaanesh Case 1: Baseline Raptors.
The raptors are still taking 0.83 wounds, but now strike back without losing anyone. On the charge, they get (9x3)+4 = 31 attacks. That gives 6.89 wounds (and dW = 6.06).
Slaanesh Case 2: Power Fist.
Assuming the aspiring champion survives, the raptors get 9x3 regular attacks, plus 3 power fist attacks. The regular attacks cause 6 wounds; the power fist yields 1.25 wounds. That's 7.25 wounds in total (dW = 6.42).
Slaanesh Case 3: Lightning Claws.
Again, we'll assume the champion survives. The regular attacks again cause 6 wounds. The lightning claws have 4 attacks, of which 2 hit and 1.78 kill. That gives 7.78 wounds (and dW = 6.95).
The Icon of Khone is still superior. The extra attack still outweighs the increased initiative. Good job since I've already modelled the Icon of Khorne and don't particularly want to change!