A good army to beat Karador on impossible with a paladin?

[Vilk]

Originally Posted by DGDobrev

After everything is cleared out, poison cloud over the bone dragons, magic spring on them and get resurrecting. I left the poison cloud at lvl 1 (doing 20-40 poison damage for 10 attacks) and the bone dragons were taking only 3-6 damage from the cloud and giving back a lot of mana. Sweet.

I tried multiple time to use a similar trick even if poison cloud wasn't at level 1. I got many problems because the cloud is moving to reach enemy.

I noticed few cases where the cloud didn't move but it's not fully clear when this happen.

It seems that if the cloud won't be able to reach opponent before exhausting then it won't move. Also in case of Karador fight if you end with the crystal the cloud won't move as it doesn't consider the crystal as an enemy.

It seems that some obstacle can block the cloud but it's not clear what obstacles.

When trying to see if the cloud could reach the enemy and then will move I think, not sure, that I have to count the number of attack of the could + 2 from the square I cast the cloud and including this square. That's also a reason to not improve the cloud because it will move on a longer distance.

I was wondering if you have quoted other characteristics that allow to identify when it's fine to use it or not.