Just for fun:
Imagine a creepy pitch black underground or cave tunnel system. This would be a labyrinth you could only see in if using lanterns or by lighting torches/fires. These depths would be infamous as the most terrifying PvE part of the map, with a sinister creature(s) like a soul stealer or something of the sort. Hard to kill, full of jump scares, eery sounds, it would feel like a dark Indiana Jones dungeon adventure. In the depths of the darkness, a highly valued treasure would spawn in random places, making the search different each time. If a competing crew were to show up and enter through a different passageway, things could get really intense (especially with the mimic dart).
Just a thought; no lore even required.
