Hokay, here's all the new stuff I was able to quickly find on these guys. If someone with more GURPS experience (I'm having trouble downloading the GURPS Lite roolbuk) could take the racial stats for them and convert them into more ordinary measurements--this tall, this heavy, this fast, etc.--I'd be obliged.
First of all, Ghols (as we thought) probably aren't inherently evil. They simply lack sufficient self-restraint to develop a civilization, and so are naturally hostile toward the mainly-civilized Light. Their position is, perhaps, a more extreme version of the position of the fir'Bolg prior to the alliance between Caliban and ou'Kahn.
Ghols' hearing is superior to that of humans, but their other senses are not. They mature more quickly than humans. Apparently Ghols can touch, eat and digest many substances toxic to most organic races, and have superior immune systems making them extremely resistant to disease--useful powers for a carrion-eater who spends most of its time hanging out with the undead. The book doesn't say, though why these powers protect them completely when carrying wight parts, but don't protect them completely when struck by a pus-based attack. I'd hypothesize a Ghol's skin and mucous membranes are chemically impermeable to wight toxin (it can't penetrate the membranes of the outer cell layer), so that it isn't hurt by simply holding a piece of a wight; but when a Ghast punches it, or a wight polyp strikes it, the force of impact drives some of the toxin into the Ghol's body through pores and fissures in the skin, and the Ghol suffers accordingly.
Ghols are, on average, less intelligent than humans, but individual Ghols may be quite clever by human standards. However, they have little or no interest in education and so become shrewd rather than wise. They've never been known to use magic. They take little care of their children, and most are killed before they become adults. Ghols have no names until, at adolescence, they name themselves.
The Ghols possess a gold idol to the Dark Gods called the Crom Cruach, the whereabouts of which are known to no other race. They sacrifice children in front of it--their own if they have captured none of other races--to gain the favor of those gods. Some believe it may be one of the Rune Stones of the forty-nine dreams of Wyrd, though I fail to see how it could simultaneously be this and an idol to the gods which are Wyrd's enemies.
Ironically, the Ghols' feud with the Dwarves has made them more interested in civilized life. The conquest of Stoneheim gave them the opportunity to see the advantages of a city-based society, and they've learned to operate many of the Dwarves's technological artifacts, including cannons, as or more skillfully than the Dwarves themselves. If they continue to inhabit Stoneheim, it's possible that the Ghols will develop a full-fledged civilization. Perhaps (me talking, not the book) fear of this is one of the main reasons for the Dwarven dedication to retaking Stoneheim.
Ghols currently range through most of the known world, raiding and scavenging, and even dare to enter Forest Heart, though they seem more wary of the Trow. They have no static dwelling places, save for Stoneheim. If apparently harmless, they aren't slain on sight by most of the Light races (Dwarves an obvious exception), but their reputation precedes them and they will find few friends among the civilized peoples.
Oh, and the Ghols who conquered Myrgard and Stoneheim in 2431, the same year as Muirthemne's fall, were explicitly working for Balor already.
Mauls, like Ghols, aren't truly evil, but they have terrible tempers and not much restraint, and so they tend to ally themselves with Dark forces who consider those qualities assets rather than flaws.
Mauls are sharp-toothed and are carnivorous by choice, though they can eat vegetable matter when necessary. Like pigs, they greatly enjoy eating snakes (I wonder if they ever got into any hassles with the Skrael?). They can lower their daily consumption to human levels for long periods of time--when they have the opportunity, they will bulk back up by eating seven times as much as a human. Mauls have very good hearing (even better than Ghols), but their vision is poor. Their tusks are not used offensively, but provide their faces with protection from blows. Mauls mature more quickly than humans. Though they take good care of their young, childhood mortality is high (something like 85%), for reasons unknown to us.
Mauls are apparently less intelligent than any of the other tool-using races. However, they work hard at using what little brainpower they've got, and so their practical problem-solving ability is--on average--about as good as that of the Ghols, who are smarter but more distractible and less motivated. No Mauls are really clever by human standards, though, and they have difficulty assimilating new ideas and modes of life. They have foul tempers and are naturally inclined to settle all disputes by violence, but they can be slavishly loyal to their chosen master.
The homelands of the Mauls, the Blind Steppes, are so named because they are shrouded by fog for nineteen days out of twenty. The Steppes are supposedly home to large (even larger than the Mauls) predatory creatures. Here the Mauls live in nomadic hunting tribes of about 200 adults and 400 children. Every 13 months or so, several tribes meet up and exchange mates; single young males often switch tribes at this time. The Mauls have little love for their home, and would dearly like to inhabit warmer climes, but they dare not make war against either of Most Mauls choose their weapon--usually that wooden club--early in life, and then use it exclusively and frequently for hunting, warfare, and even some forms of social interaction. They make the leather armor on their torsos and also wear shields and armor scavenged from other races.
Since Soulblighter's demise, the few Mauls he left behind in the west have been trying to make their way home; attempts at settling in the West have been firmly discouraged by the Empire. The Mauls in the Blind Steppes make sporadic forays into human territory but have no immediate plans for a serious invasion.
Supplement me, correct me, refute me. (Sounds like the motto of some Enlightenment-era Parisian philosophers' club.)
--SiliconDream