Game mode: Both
The following thralls attached to Flawless Epic sets only have a single spawn point inside Relic Hunter City that seems to be blocked by a building:
Hanar of Bossonia: Aquilonian set
Arcen Brokenfingers: Shemite set
Zoara of the Marshes: Stygian Soldier and Stygian Raider sets
Ghamm the worn: Zamorian Thief set
There are also two other named thralls that spawn in this place.
The said building is located between the large building at the center of Southlake and the house with the slightly open door to the south of it. It’s very visible at night because it has a misplaced orange glow coming from inside. The spawns can easily be observed by ghosting into the building.