Old-School Essentials Goes to Hell and BackerKit With Demonic Grimoire

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This May marks the first ever Old-School Essentials Month, a celebration that will feature over a dozen official and third-party products for the popular OSR system.

The centerpiece of the event, however, is the Demonic Grimoire, the first major official rules supplement for Old-School Essentials. Written by OSE creator Gavin Newsom of Necrotic Gnome in conjunction with publisher Exalted Funeral, the book is designed primarily for Referees looking to inject their campaigns with more demons, devils, fiends and hellish horrors. The crowdfunder was fully funded within a few minutes of launching, but runs from now until June 5th, 2026 on BackerKit.

Below, we head into the sulphur-choked depths of the Abyss to drag up all the details.

What is Old-School Essentials (OSE)?

Old-School Essentials (often abbreviated to OSE) is a fantasy tabletop RPG based on several of the original Dungeons & Dragons systems from the late 1970s and early 1980s. Created by designer Gavin Norman (founder of publisher Necrotic Gnome), OSE is designed to capture the feel of early tabletop gaming without the confusion and usability issues often found in rulebooks from that era. In particular, rules in OSE are designed around “control panels,” presenting each topic on two side-by-side pages for easy reference. The Referee (the OSE version of a Dungeon Master) also takes an OSR approach that favors “rulings, not rules.”

Since its release in 2019, OSE has become one of the cornerstones of the Old-School Renaissance (OSR) movement, with the game releasing core rule books along with adventures, zines, supplements and accessories. Currently, there are two OSE formats: Old-School Essentials Classic Fantasy (which is essentially a clone of the 1980s D&D Basic/Expert rules) and Old-School Essentials Advanced Fantasy (which is inspired by the rules of AD&D first edition). Notably, both systems are also fully compatible with pre-existing supplements and modules from the early days of D&D.

In November 2025, creator Gavin Norman announced that a new OSE update was in the works, which would remain completely compatible with all existing OSE content, and would offer new artwork and minor rules tweaks, rather than being a completely new edition. This updated version is now available as part of the Demonic Grimoire BackerKit campaign.

What is Old-School Essentials Demonic Grimoire?

Demonic Grimoire is a 176-page supplement that focuses primarily on devils and demons (two monsters from the original D&D B/X system that were noticeably absent in previous OSE Materials). The book is primarily designed for OSE Referees, but does contain some player options. Key content includes:

• Demon Lords & Cults: Detailed profiles on 8 demon lords (including Infernus, Phranax and Sillith) complete with lore, stats and details on the various cults that serve them.
• A Bestiary: Includes stat blocks and illustrations for over 60 demons, devils and infernal creatures inspired by AD&D classics, as well as new monster designs.
• New Player Options: Four new character archetypes, including the Chaos Knight, the Cultist, the Demon Hunter, and a new Tiefling race/class.
• Dark Mechanics: Detailed rules for magic circles, summoning rituals, demonic pacts and 70+ artifacts of infernal power.

What are the Kickstarter backer options for Demonic Grimoire?

The primary draw of the Kickstarter is the core sourcebook (which comes in a standard OSE hardcover format, as well as PDF), which does require the base OSE rules to use. There are, however, a number of additional products and accessories, including:

• Deluxe Limited Edition: A custom version featuring a leatherette cover with matte red foil that’s designed to look like an in-world occult tome.
• Demonic Grimoire Monster Deck: A reference tool featuring 60+ tarot-sized cards with art on the front and stats on the back.
• Golden Lies Adventure: A short, demon-themed “Quick Delve” adventure designed for Level 4 to 6 characters.
• OSE Core Books (2026 Printing): Backers can also pre-order the updated OSE core books, which feature 200 new illustrations, minor rules adjustments and optional AD&D-inspired rules (the release date for this new books has not yet been determined, but Necrotic Gnome has confirmed that the books will be shipped before Demonic Grimoire reaches backers).

The specific backer tiers on Kickstarter are as follows:

• Acolyte ($15): The Demonic Grimoire PDF.
• Ritualist ($33): The Demonic Grimoire hardcover edition with PDF
• Demonologist ($55): The limited edition hardcover plus the PDF.
• Reeve of Hell ($85): Both the standard and limited edition hardcovers, plus the PDF.
• Elder Ritualist ($120): The standard hardcover and PDF, plus the 2026 printings of the OSE Player’s and Referee’s books.
• Elder Demonologist ($142): The limited edition hardcover and PDF, along with the 2026 updated OSE core books and PDFs.
• Lord of Hell ($220): The “all-in” tier featuring both versions of the Grimoire, the OSE 2026 core books, plus all of the accessories.

One other thing to note is that as part of Old-School Essentials Month you can also access group shipping from many of the other publishers releasing OSE content during the event.

Why We’re Excited About the Demonic Grimoire

• The first major OSE expansion: Old-School Essentials has become incredibly popular over the past few years, but this marks the first major supplement, which is perfect timing given that a new updated version of the core rules is coming out in late 2026.
• A powerhouse design team: Necrotic Gnome and Exalted Funeral look like they’ve really upped their game when it comes to the OSR-style of art and design. The deluxe version of the supplement in particular, looks absolutely epic.
• The missing demonic link: Longtime OSE fans have noted the absence of demons, devils and infernal monsters/magic from the game. Including them now feels like a smart move.
• 100% Ready to Ship: In a rarity for crowdfunding, the project is already done, with writing, editing and art completely wrapped up. That means if you’re backing it, you should expect it relatively quickly compared to most TTRPG crowfunders.

Final Thoughts

Old-School Essentials has become one of the most influential games in the OSR, so it’s great to see the system continue to evolve with a major new supplement that also covers some of the most iconic infernal monsters and themes from B/X and Advanced D&D. Whether OSE fans are willing to go to Hell and back to get this new supplement, however, remains to be seen.

The crowdfunder for Old-School Essentials Demonic Grimoire runs from now until June 5th, 2026 on BackerKit. Below is also a short trailer video from the Exalted Funeral YouTube channel with more details on the campaign.