[quote=Ink Blood]
I wonder that too. I doubt illusions would work on them, but I don't think constructs would just collpase near them. Otherwise why didn't they just send Guardians into Malfear's ranks of undead to disrupt them and get rid of his armies?
[/quote]

Yes, I think that they're immune to illusions, and maybe they have an easier time against constructs? That's uncertain, I don't think magic would simply dissipate once they're near it.

Maybe constructs can't see guardians? That might make sense, maybe?