I’ve been attempting to penetrate the secrets of the Depths lately. There’s not a whole lot to go on but I’m beginning to think they’re the games’ version of the Underworld. We know a long lost civilization mined from them but how they transported the materials to the Surface isn’t explained (yet). The layout directly mirrors the layout of the Surface with key locations having an analogue and the Goddess Statues on the Surface are represented in the Depths by Bargainer Statues, which gather up souls. On that note, the region is filled with Poe’s which are the series’ ghosts and has altars and temples scattered throughout. I’m going to go out on a limb here and say that I believe that these represent fallen comrades and the like. Monsters are also much less in number while Gloom covers most of the region. More research is definitely required!