OSR: The Monster Overhaul Update - Main Text Complete

All 20 monster chapters of the Monster Overhaul are complete!


In their revised order:

1 2 3 4 5
People Dungeon Dragon Thinking Beasts Heraldic Beasts
Lucas Roussel Robin Carpenter
Iguanamouth Lucas Roussel Iguanamouth
Adventurer Giant Spider Ancient Dragon Harpy Basilisk
Barbarian Goblin Dracospawn Kappa Catoblepas
Cultist Lich Drake Lamia Chimera
Knight Mimic Droggin Lammasu Cockatrice
Mercenary Monstrous Vermin Ethereal Dragon Manticore Griffon
Peasant Mummy Kobold Medusa Hydra
Pilgrim Myconid Pseudodragon Minotaur Owlbear
Merchant Ooze Wyvern Naga Questing Beast
Townsfolk Orc Young Dragon Peryton Strong Toad
Wizard Skeleton Zombie Dragon Sphinx Wurm

6 7 8 9 10
Primeval Elemental Divine Dark and Malign A Wizard Did It
Logan Ashlyn Rudolph     Robin Carpenter
Flying Lizard Elemental Angel Ghost Aboleth
Herd Lizard Elemental Spirit Beast of Creation Ghoul Animated Item
Swift Lizard Elemental Tyrant Cherub Necromancer Elsewhere Creature
Thunder Lizard Firebat Demigod Night Hag Eye Tyrant
Tyrant Lizard Gargoyle Devil Nightmare Beast Golem
Cave People Grue Dybuk Ogre Homunculus
Collossal Ape Living Gem Hell Hound Vampire Mind Eater
Ground Sloth Sandwalker Imp Werewolf Mutant
Predatory Plant Spitling Scapegoat Wight Rust Monster
Troglodyte Will-o-the-Wisp Visionary Zombie Shivered Beast

11 12 13 14 15
Spring Summer Fall Winter Hostile Forests
Ashlyn Rudolph Naf Luka Rejec
Centaur Chaos Frog Dark Fair Biscuit Golem Bear
Druid Firebird Dullahan Blizzard Eel Boar
Flower Nymph Froghemoth Harvest Avatar Grey Horse Dryad
Hatchling Mandrake Iron Fulmination Ice Hag Fairy
Hateful Goose Pyromancer Leafling Kamaitachi Giant Snake
Raincloud Raijū Murderous Crows Nuckelavee Tiger
Saty Skeeter Polevik Remorhaz Treeant
Shambler Sun Dog Scarecrow Snow Fungus Troll
Sigbin Thriae Shofar Ram Snow Golem Unicorn
Wicker Walker Tunnel Hulk Tempest Hag Tortoise Tsar Wolf

16 17 18 19 20
Hot Plains Mysterious Mountains Stormy Seas Strange Water Sci-Fi
Logan     Naf Frenden
Baboon Alicanto Giant Crab Abyssal Fish Alien Invader
Crocodile Alpine Specter Kraken Ancient Arthropod Alien Visitor
Elephant Ape Merfolk  Leech of Paradise Alpha Brain
Flightless Bird Couatl Pirate Mantis Shrimp Doppelganger
Hive Insect Giant Remora Marine Worm Giant Insect
Hippopotamus Noble Giant Sea Hag Predatory Snail Perfect Predator
Hyena Kirin Sea Serpent Rotifer Robot Hound
Panther Seal Sea Slug Robot Servant
Lion Roperite Shark Sea Star Robot Titan
Rhinoceros Telluric Goat Whale Tardigrade Veggie-Mite

With additional art by Dyson Logos and Scott Wegener.

All completed chapters are available on Patreon. 300 A4 pages of content (so far!). I sometimes post WIP tables and tools on twitter, mostly to instantly locate spelling errors. It's funny how hitting the "publish" button does that.

Robin Carpenter

The plan from the last update post hasn't changed.

  • Do an editing pass, focusing on numerical consistency. Some of the values (particularly treasure values) are placeholders.
  • Sort out the Phylogenetic Tree (the HD(NA) bit), the tactics section, and the alternative sorting methods.
  • More editing and testing.
  • Even more editing and testing.
  • [???]
  • Crowdfunding?


Back in 2014, SBLaxman created an extremely useful spreadsheet listing all monsters (including really obscure ones) for AD&D (1E and 2E), 0E, and Basic. It's got everything a collator might need. (Note: the AD&D tab starts with 2E selected and 1E hidden by default. Check the "edition" column).

The problem is that D&D writers never really had a consistent idea of what a HD meant, or how to format statblocks. Sure, the basic framework stayed the same, but some authors list HD as a range (3-10), some as a flat number (4), some as a number plus a fixed value (5+2), some as a number minus a fixed value (1-1), some as a fraction (1/2), some as a dice substitution (4 HD, but using d6s instead of d8s), and some as a HP value only (128 HP).

Yes, there are reasons for all these variations. It doesn't necessarily mean they're good reasons. At low HD, a flat fixed value addition or subtraction is a significant change, but at higher HD it stops meaning much. Is 8+3 HD really different from 8 HD? This issue extends to virtually every aspect of the statblock.

For the Monster Overhaul, I've mostly stuck to a a single listed HD value followed by an average HP value (HDx4. Yes, 4.5 is more accurate, but that requires extra math and, in testing, it's rarely if ever relevant). Creatures with 0 or 1 HD may have non-average HP values listed instead.

The chaotic nature of AD&D stat writing makes any sort of trend analysis difficult. Noisy garbage in, noisy garbage out. 

Still, it's an extremely handy list. If I can't assign a matching Monster Overhaul monster to something on the list, I'll need to consider if a) I need to revise a chapter or b) if that monster is worth including. Some monsters are too specific or too boring to include. I did one pass while writing the chapters; this second pass will help write the indices.

I'll also be indexing results against relevant creatures that have never received D&D stats. A Book of Creatures will be helpful.

Revised HD(NA) Section

Page 1 of 6 of the Monster Overhaul HD(NA) chart.

In a book of monsters, indexing is critical. Listing monsters by HD is one practical method, but what if, instead of a simple list, we used a phylogenetic tree? You can read about the original HD(NA) concept in this post, as well as looking at the sprawling chart for the AD&D MM, MMII, and Fiend Folio.

The HD(NA) chart for the Monster Overhaul is more compact. Part of the pruning process is eliminating low HD entries that aren't interesting (Squirrel - Ordinary, etc.) and condensing other entries into general types (Mammoth, Mastodon, etc. -> Elephant). Still, it's an... interesting chart. Did you know that Druids go through a Baboon stage? It's true!

The pages are designed to bleed into the gutter of the book, so it might look a bit odd on your screens. 

Duplicate entries in the same column are creatures with variable or tiered HD.

Final Notes

Thanks to everyone who suggested monsters to round out each chapter, found issues with draft content, or provided other kinds of useful feedback. 

If you spot any creatures that should be listed and aren't, let me know in the comments. Chances are it's covered by one entry or another, but it can't hurt to check.


  1. It's late to post now since you have done all the work and written everything but yet.
    Other possible monsters:

    Strange waters
    I found a gian mantis shrimp pic https://imgur.com/aWQZe5c
    Variation of the Sea Star: Sea Black Hole and Sea Super Nova. Sea black hole is a giant sea urchin
    It mmoves on its spikes and is unable to touch things without stabbing them. Human sized. A cursed human.
    Whatever the hell this is https://imgur.com/sqgiabh IIRC I ook it from one of the paizo pirate books. A siren singing hydra or something.

    Stormy Seas
    kelpie a water horse. https://imgur.com/uHzKDg8
    Lusca: a shark octopus hybrid. I like the version where the tentacles end up in more sharks https://imgur.com/6FL93e9
    Giant Sea serpent. https://imgur.com/bMELciF Or undead giant sea serpent.

    1. It's not too late! As long as the book isn't published, it's all just easily reordered 1s and 0s.
      -Giant mantis shrimp is in there. I'm a bit inconsistent about when I use "Giant" prefixes. I figure everything in the Strange Water chapter is so strange already I don't need to specifically point out that it's oversized.
      -I like those! I've already got the sun-theme with the Sun Dogs, but maybe I'll add a cross-reference.
      -I have no idea what that Pazio thing is either but it's excellent.
      -Kelpie has a few options for cross-references.
      -Lusca is definitely a Kraken of some sort.
      -Sea Serpent covers big creatures, but for an island/world serpent, a Beast of Creation should work.

    2. Thank you for the suggestions though! All very helpful, especially for index-building.

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  3. Hey, how do I get on the mailing list for the kickstarter(or whatever)? I'm very hyped about this and would love to get it as asap after it's published.

    1. I'll announce it here, on twitter, on Patreon, etc, so any one of those methods should work.

  4. I'm late to the party, sorry.

    I tried to find if anything was missing, and I think you've done an amazing work with category (ontological?)

    So just checking :

    Jellyfish/Coelenterates(name from alternity GMC guide)/Radially symmetrical creatures would be in a "Not another phylum arthropods generator"?

    Squid would be similar to a small kraken?

    Kelpie/sea horse/hippocampus would be functionally similar to seals?