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The Extensive Eldritch Expansion



A set of cosmic horror inspired subclasses, character options, spells, monsters, items, and DM tools.

The Extensive Eldritch Expansion is exactly what it sounds like: it will extensively expand the eldritch qualities of your Dungeons & Dragons games! The goal here is to integrate elements of cosmic horror seamlessly into the existing game; You’ll still be playing D&D, just with some added monsters, items, effects, and the hallmarks of a type of fiction typically only mentioned briefly brought more into the spotlight.

What You’ll Find Within

Chapter 1 introduces five new subclasses with some cosmic flavoring: The teleporting Dimensionalist Artificer, the mutating Path of the Primordial Barbarian, the dark Void Domain Cleric, the actually-eldritch Aberrant Knight Fighter, and the parasitic Apex Being Warlock.

Chapter 2 adds more character creation options for players in the form of the Mutated lineage, four backgrounds, and five optional features.

Chapter 3 grants 11 new spells for players and DMs to spice up their casters.

Chapter 4 includes a set of tools and mechanics to help DMs plan and run a cosmic horror themed game, the highlight of which is a completely revamped madness system.

Chapter 5 is host to a menagerie of 44 original monsters complete with stat blocks and lore, as well as other helpful information regarding cosmic monsters in general.

Chapter 6 features 10 new magic items, including a few artifacts, and a table of 100 eldritch trinkets.



Author & Designer: Alexander Vigna

Feedback, Proofreading, & Consulting: John Price, Kitsunefourtail, Aurelia Cetinn

Commissioned Artwork:

by Stacy Wead -

Page 68: False Celestial, Page 83: Mind Flayer Variants, Page 100: Blindfold of Seeing, Page 101: The Golden Cloak, Page 103: Mind Rune Machine & Runes, Page 104: Moonlight Blade & Parasite Sword, Page 105: The Profane Crown, Page 106: Tentacle Whip & Staff of Madness

Other Images: Made by Alexander Vigna using a mixture of Midjourney AI, stock photos, and custom Photoshop editing and compositing. This book features no raw, unedited AI-generated images. AI software was used only to generate portions of images for compositing purposes, or base images for touch up editing and color correction, by me, a human.

Author’s Note: While my opinion of AI-generated images has shifted more negatively in recent weeks, I wanted to release it while the OGL 1.0a is still active ASAP, rather than spend more time swapping/removing images. Yes, I know the OGL 1.0a doesn’t really apply on DMG, but better safe than sorry.

Special Thanks: My wife, for putting up with this nonsense, Anyone I’ve ever played D&D with, The Spellbook Gaming peeps, From Software, for Bloodborne, Nuwan Panditha, and his Painterly Photoshop action, Pexels, Unsplash

See my other content:

Content Warning:

This book is designed for use in horror-themed games. If you are particularly unsettled by the tropes of cosmic/eldritch horror, you may wish to steer clear of this book.

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Richard M January 24, 2023 11:32 pm UTC
10$ release still uses AI for it's art....
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File Last Updated:
January 20, 2023
This title was added to our catalog on January 20, 2023.