I encountered Dowan in this area. Duvessa was nowhere to be found. When I killed Dowan, I didn't hear her distant scream. Then I realized, Duvessa must have been cooked by the flames before I ever saw her. I went back in the text log and Dowan did shout: "Her death will not be in vain!" So she was there. It wasn't a bug where somehow Dowan appeared alone. His sister just got toasted by the dungeon itself.
I've never got this far with a spriggan before and I'm not sure where to go with it. My understanding is that the new Slime is extremely dangerous and Vaults 5 is probably lethal, as well.
I guess that means I go Abyss, but I generally do not do well with Abyss and have only collected that rune once or twice before (and once was mostly by accident, having been banished right beside the rune chamber).
I will clear Vaults 1-4, and possibly some or all of Depths before going for the third rune, to make sure I am strong enough to do it, but I am genuinely unsure if I should go Abyss or attempt V:5 just because that's what I'm most familiar with and what I most often have done for my third rune.
I'm also thinking it might be time to swap my amulet for something else. That +3 slay and the extra damage output from harm have me killing things fast, but the extra incoming damage is starting to become more of a liability not that there are more things that can fit me from a distance.
Char dump: https://pastebin.com/cRgivr3q