Sandcastle is unique in many ways, but mostly in that the average height of the inhabitants is around 4'5" give or take an inch. The primary occupants being non Humans, the race once known in the age of myth as the Halflings, more recently referring to themselves by the term Halvingen who live alongside the Duardin. In actual fact have done for many generations, of the Halvingen at least.
Picture if you will, A location which is much like the shire from LoTR, surrounded by sheer sandstone cliffs with dwellings carved out by the Dwarves (think the library at Petra, Jordan) and you will approach what sand castle is.
it's a wonder that such an area would be overlooked by Nurgle during the age of chaos, but the Mawtribes of the Ogor Hinterlands may well have acted as a reasonable buffer/distraction for the god of corruption, so the Emerald Isle went largely untouched.
It's said that the way to an Ogors loyalty is through their Gut and the Halvingen excel in the culinary arts, and as such, there are Mawtribe members who feel a kinship for these strange diminutive folk who occasionally stray into their lands looking to trade.
That's pretty much where I'm at with my Cities of Sigmar Army.
it's going to be Dispossessed, Halflings and maybe an Ogor Mercenary or Two.
I might see what else I have to use, and see what humans I have.
also, I want to thrash this out a bit more. but we will see where we go with it.
