Chaos structures.

Wow :eek:, so that's why it doesn't work out very well, because I hit them too hard. Conclusion: they need to be taken down with ranged attacks and magic :D. The downside is, I don't remember if they have magic resistance :confused:?

That's exactly it - let's say you deal 600 damage with one hit, which means you kill ten Imps. The attacking squad's shield will absorb 200 HP!
Moreover, if I'm not mistaken, Fire Shield doesn't care about retaliation, meaning you can lose a good number of units, even, for example, Vampires, when fighting Imps. Also, Fire Shield deals damage even after the squad is completely destroyed!

In the expansion, they are definitely immune to fire, and therefore, fire damage spells won't work. ;) As for Whirlwinds, I don't remember - it seems like fire has a slight effect on them.