Shadowstrike Starhost
Skink priest must see the frostlord
5 x chameleons (shooting from distance)
5x chameleons (shooting from distance)
3 x Terradons (apears 3" from frostlord, flying around to drop the cargo and finished move 3" from FL, shooting sunleech bolts, charging)
2x assasin hiden in terradons (both with relic blade, with makes thier weapon D3 + 1 damage against heros
I Killed the Frostlord in Turn one
You are devoting to the task a full battalion, 720 pts, and you still need some really serious luck.
On average, you will do 2-4 mortal wounds (so the FL takes 1-2 wounds).
At that point, given that the FL saves on 3+, you need to do, after all your attacks... 65-75 potential wounds.
Let's do some math, with average rolls.
mortal wounds from terradons on a 4+. 1-2 will do it, so 2-4 wounds.
The FL takes 1-2 wounds, now it's at 11-12 wounds.
shooting from Chama skink: 20 shots.
to hit at 3+, rerolling 1s: 16 successful hits
to wound at 4+, rerolling 1: 6-7 normal hits, 2-3 special ones.
you threaten 11-13 wounds
Terradons. You can have an Alpha (leader that shoots) or a master of the sky (leader with skyblade).
Let's say Alpha.
shooting: 3 shots
2 to hit at 4+, 1 at 3+, rerolling 1: let's say 2, so 2d6:
7 to wound at 4+, rerolling 1s:
you threaten 4 wounds
Terradons' charge:
12 to hit at 4+, rerolling failed ones, 9 hits
9 to wound at 3+, rerolling failed ones:
you threaten 8 wounds
Assassins:
12 to hit at 3+, 9 hits
9 to wound at 3+, let's say 5 are successful at d3+1:
you threaten 15 wounds
After the mortal wounds, the FL still got 11-12 wounds. you are threatening a potential of 40 wounds with no rend: the frostlord will save one third of them, halving the other ones.
On average, the FL will be alive with still 5 wounds.
Can it be done? well, if you did it, yes. But you really need the favor of the Dice God. Employing 720 pts vs 460 pts.