Demon Portal prevents end of combat if..

[Zechnophobe]

Originally Posted by DGDobrev

The spider example is a different matter. First of all, you need to kill all stacks of spiders to actually win this battle.

I found a similar thing, but with different mechanics. Black Dragons are supposed to be immune to all magic, but hero-cast plague affects them, and cannot be dispelled because he is immune to dispel I guess the BD's are not so immune to magic afterall

I've always wondered why BD's can get plagued. It makes for a pretty impressive debuff I must say. Drops their health and defense down by a goodly chunk.