Regarding Celene's inquiry, Hill actually has some understanding, but he can't explain it.
How the Undead Tribe managed to clear such large, safe, danger-free tracts of land in Neverwinter Valley so quickly is definitely because they used their packages very flexibly.
Doing so, at least when a trap is triggered, people can be a little further away, and if they're lucky, they survive... It's hard to imagine how much blood and tears it took to become so clever.
Moreover, Hill also saw some bricks from the Succubus Queen's palace on Giant's Ridge Mountain, probably because someone also participated in the activity of dismantling the palace to sell, but either forgot or thought the money wasn't worth the hassle, so they didn't care.
