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The Concordance of Abyssal Layers

You wanted to know the chant about the Plane of the Abyss? Fancy yourself a real blood do you, or are you just an addle-cove? I am the Mimir of the Nadir, a magical construct designed to provide information on all topics Abyssal.
Use the table below to search through my Concordance of Abyssal Layers. You can use the search box and filters to narrow down the data. For example, use the incantation ‘graz’ to see all the layers controlled by Graz’zt and/or use the filters to show only the interdicted layers. You incorrigible rebel, you!
A disclaimer: By utilising this information, you acknowledge the risks and that you absolve this mimir of responsibility for any untimely deaths (or worse) that may occur as a result of any misadventure.
See also: Overview of the Abyss |Â Codex of Completed Layers | Who’s Who | Counting the Layers, a discussion of the layer numbering methodology of the Fraternity of Order.
Mimir, tell me about the layers of the Abyss…
Source: Data compiled and cleaned by Jon Winter-Holt, using information pooled from 1e-5e D&D canonical sources, third party references, fan generated content and original homebrew material.

Did you just name The Wells of Darkness “Moscow”?
Yeah I was wondering about that one as well. Not my creation, I got the alternative name from here. I’m not sure where THEY got it from though!
https://realmofadventure.fandom.com/wiki/Moskva
This is the most incredible resource I’ve ever discovered and I wish I had had it when I was routing the Abyss in 2018!
I surprised you decided to stop at layer 665 and didn’t go for the 666th layer.
Heh heh, gotta leave some mystery. But seriously, several different fan-made layers were all numbered 666. I don’t think any one of them should get such an auspicious number, so I renumbered all of them and left 666 (and beyond) free for future use..
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I have a homebrew layer (579) that you may or may not be interested in for this list.
I’ve written on its lore for years through various short stories and gameplay settings.
Hey Karlo, sounds intriguing! I’d love to hear more, please drop me a message with your reply address through the contact form and I’ll get back to you!
I’m having a lot of difficulty tracking down additional information about some of the layers, i.e. Sylthiand. Could you perhaps add the sources, or outline if they’re author originals?
Thanks for the feedback. Unfortunately my original notes were made in an era where they were originally intended just for my eyes, and annoyingly I neglected to record a lot of the sources! I’ve started combing through my notes to try and add in where they’re originally from. I’ll update the table of layers as I unearth more detail. First thing I’ve added is a flag to show what’s ‘official D&D canon’. For now, safest to assume that everything else is homebrew of some kind or other.