Races are a controversial topic. There are two ways to go about them. The first is to be exclusive. Permit only those races that were in the 3rd edition incarnation of the Scarred Lands. The second is to be inclusive. Since the first is something anyone can do, and it’s more of an intellectual challenge to be inclusive, let’s try the the second one out and see what we can say for each of the races — and how to make them very Hollowfaust in particular.
Dragonborn: When I first ran my 4e Hollowfaust one-shot, a Guildsman PC carried a dragon’s tooth that when he cast down, sprouted a powerful dragon-warrior. Dragonborn may be creations of this nature, rare spartoi made from priceless dragon’s teeth.
Dwarves: Already accounted for in the Scarred Lands and Hollowfaust in particular.
Eladrin: The forsaken elves have a very interesting fey take on them that would match the eladrin fairly well.
Elves: Accounted for in the Scarred Lands. Elves in Hollowfaust might be happier in green and verdant lands, but reside in the City because the Hornsaw is too dangerous.
Half-elves: Rare, but accounted for.
Halflings: Accounted for.
Humans: No commentary needed, right?
Tieflings: They seem to fit right in. I would assume most come from bloodlines established in the Titanswar, though the general reshaping of mortals associated with some titans like Golthagga would work. Tieflings might make pilgrimages to Hollowfaust in particular because the populace is pretty accepting of weirdness if you’re willing to abide by the law. Also, the tiefling statblock could work for peculiar children born in dead Sumara.
Deva: Like the tieflings, they could be from the Titanswar. They seem particularly suited to Madriel, but a Nemorga-specific group of deva (“Children of the Silent Angel”?) would of course find their way to Hollowfaust if they existed.
Gnomes: Potentially another race from the Hornsaw.
Goliaths: They seem tailor-made to fill the role of the Davaka barbarians in the nearby Gascars. Titanspawn, perhaps, but I’m inclined to say that they could also be another variant of human like tieflings or devas. If titanspawn, they’d be admirable spawn of Denev, and therefore likely acceptable.
Half-orcs: As noted in the book, there are many in Hollowfaust.
Shifters: Perhaps they have their origins in the Hornsaw. Certainly the Halloween-ish feel of Hollowfaust could benefit from “werewolf” PCs.
Githzerai: I figure a default Scarred Lands take would have them tied into the slarecian legacy.
Minotaurs: They do seem like a titanspawn race, but the Guildsmen might offer asylum to an individual clan if the motivation was there. I would gladly have integrated a clan wandering the Dead Quarter, fur painted with the ashes of the dead.
Shardminds: Two possibilities come to mind. One is actual living creations of the Animator’s Society — entities of bone inhabited by ghosts. Perhaps all the necromancers could save was a hero’s soul, and they found it a new and strange home. The other possibility is the shard-ghost, a creature of obsidian and volcanic ash risen from the Dead Quarter. Such creatures would be a little intimidating even to the citizens of Hollowfaust, but if they were adopted into the Guilds, then they could find acceptance.
Wilden: The wilden seem exceptionally well-suited to show up as creatures of the nearby Hornsaw. Likely the “forever outsider” role within the city.
Gnolls: Perhaps a tribe from the edges of the Ukrudan, who acted as mercenaries during the wars with the sutak.
Shadar-kai: Probably not a separate subculture — just some of the singular children born in Hollowfaust, products of the powerful necromantic energy. Possibly children of Guildsmen.
Revenants: Obvious as the snout on a flense-drake’s face.