Goblins are one of the most common humanoid inhabitants living in the caves beneath the Kargarath mountains. They are small but usually bad-tempered and they tend to come in groups. So, this might be reason enough to not underestimate them. Moreover, they have shamans and warlocks in their ranks which are able to channel an unpredictable type of ritual magic. These days, it seems that the goblins completely have taken control over the lost dwarven dungeon of Berethil.
After centuries of an ever-sustaining conflict, trolls probably are the most lasting and well-known enemies of the Berethil dwarves. They are not as numerous as the goblins, but most of them are sturdy and big so they make up dangerous enemies in combat. Fortunately, at least, they do not wear armor and tend to use archaic weapons. Recently, they seem to have forged some kind of alliance with the goblins.
So far, little is known on what the Berethil chronicles describe as the Undead Plague of Kargarath. While some of their minions might have been faithful and honorable heroes during their lifetimes, a kind of unholy magic has eventually turned these cursed souls into sinister and restless abominations. Notably, the ranks of the undead seem to consume any kinds of species. Once they have been converted, even those who were bitter enemies during their lifetimes fight side-by-side after death.
An ancient dwarven lore tells about a baneful encounter with demons at a time which lies long in the past. While the lore lacks further information, at least it has been passed on that large tunnels have been brought to a collapse and additionally locked with powerful magic seals.