I'm currently accomplishing the hunting challenges, and the 9th challenge is to kill a Ghul Matron in the game.
I went through quite a few discussions onto Steam/IGN etc. boards, and mostly they discussed how the Matron's weakness is fire and explosions, and how to get rid of them easily. They do mention something along the lines of:
you'll need to hang out around ghul mounds at night to get one to come out iirc.
I've been stuck trying to go through caves and all kinds of seedy areas at night times and have only found orcs gatherings or Graugs. I did not encounter any ghouls at all.
Is there a particular Ghul-rich cave? A particular place in the maps (either of them)? Are ghul mounds something different? I just thought that they especially gather around caves and that is what the quote above is referring to?