Couple of questions..

[Affliction]

Hi everyone,

I'm currently playing Mage on Hard after finishing game as Paladin (Normal). I'm working my way around Rusty Island and Verona. My current troops are both types of Droids (though I'm running short on ranged type, only about 35/60), Assassins, Royal Snakes and Demonologist. I'm trying to get Grand Strategy achievements, because extra leadership would be sweet, but it's very hard. I rezz my troops by sacrificing melee droid and then resurecting them with ranged ones (they can ressurect huuuuge number of them).

My damaging spells aren't really powerful at this point and I don't have much to use. Only flaming arrow, poison and fireball.

I have questions regarding achievements:

Battle Alchemy (bonus fire and poison damage) seems to only work on my troops and not spells?

In some achievements, there is mention of spells I have never seen on my 1st walkthrough - like Armor of Gods and Magic Shield. What are these spells?

Where can I find Trap spell? There was one in robber's den on 1st island, but I didn't have gold to buy it at the time and once I defeated enemy hero there, there's nothing to buy. I'm asking this, because on my 1st walkthrough, I didn't find this spell at all.

Thanks! Might be I have more questions, but that's for the moment.