[DF] Flame Lord and Cold

[Onkl]

Hi guys

Just a quick question because I am not sure if I understand the implications of Unkillable 1 (Achilles Heel, Cold) correctly, so let me make an example:

A party encounters a Flame Lord, they do not possess any weapon or spell that does "cold" damage. They have to batter the Elemental down to -10xHP - so much is clear from the text on DFM1:15.

Let's say the party has the Elemental down to -39 HP, a new Adventurer joins with an Icy Weapon and hits the Elemental, doing 4 cut + 2 "cold" as follow up. The Flame Lord is now down to -45 HP.

How many Death Rolls would the Flame Lord have to after the attack?

3 (Because the cold effect of the weapon is enough for it to have to reroll all the called for HT rolls under "normal" circumstances)
1 (Because of the cold effect and the target being below HP at which a death roll is called for)
0 (Because the cold damage did not itself push it over a "deathroll" threshold)

Cheers

Onkl

ps. Which brings up another point I am very much intersted in: Which Spells actually do make cold damage. Does an Ice Dagger do "cold" damage in addition to it's usual impaling damage type?