That being said, I've written before in the philosophy of OSR+ that I'm not trying to re-invent the wheel. I'm trying to lay the foundations of a universal system that serves the particular style of play I enjoy—something fundamentally simulationist with a sprinkling of storygaming mechanics, a kind of middle ground between PbtA and the old school revival. Thus the monsters of OSR+—at least in this initial bestiary I'm creating for these core rules—represent an exercise in translation and taxonomical classification rather than reinvention.

On Translation

Step #1: Scour the ancient texts to identify the fundamental monsters that inhabit our cultural consciousness.

Iconic monsters come from one of three categories of origin: real world folklore or mythology, literary tradition, or pop culture. For example, the Catoblepas and the Cockatrice and the Sphinx are cryptids with rules and ecology that precede literary fiction. The Shoggoth and the Jabberwock and the Grue were imagined by H.P. Lovecraft and Lewis Carroll and Jack Vance respectively. And the Owlbear, Intellect Devourer, and Beholder (in addition to being intellectual property) entered the cultural consciousness because Dungeons & Dragons kickstarted RPGs as a genre. But all are iconic in fantasy by virtue of time and tradition.

So in building the OSR+ bestiary, I had to decide which monsters were worthy of being included in the core rules on the basis of their "iconicness," across these three categories of origin.

By the Numbers

I didn't want to go with gut feelings, however. A lot of monsters I'm unfamiliar with or just never found that interesting, but I didn't want my biases to blind me to their importance in the fantasy canon. To this end, I decided to review a list of highly lauded bestiaries in trad gaming and check it against an incredibly handy spreadsheet called The Average Bestiary that some maniac created, which meticulously catalogues every conceivable fantasy monster in existence on the basis of the frequency of its appearance across a comprehensive list of the most popular trad RPGs.

The key bestiaries I chose as inspiration include:

• The 2e, 3e, 4e, and 5e Monster Manuals
• The 13th Age Bestiary 1 and 2
• The Creature Catalog
• The Fiend Folio, 2e and 3e
• Mordenkainen's Tome of Foes
• Pathfinder 2e's Bestiaries, 1 and 2
• Swords & Wizardry's Monstrosities
• The Monster Overhaul
• The Tome of Beasts 1 and 2
• Volo's Guide to Monsters
• The Tome of Horrors

Needless to say, I found that my small sampling above comports with the widest threshold of popularity for monsters in The Average Bestiary, as far as pop culture origins go.

Why Not Indies?

Most indies that attempt to emulate a particular genre have monsters unique to their setting. These games have really fabulous ideas, but nobody's ever heard of them (which is why they're fabulous). I decided that if the name of the monster isn't enough to evoke what it is on its own, then it isn't iconic enough to be part of the core rules.

Some Other Qualifications

I also had to set some ground rules to narrow down the list even further:

In the end, this has left me with approximately 300+ iconic monsters for a core rules to draft!

Not a bad start, albeit a daunting one.

On Taxonomical Classification

Organizing 300+ monsters in a bestiary in a way that's useful to GMs requires meticulously categorizing them so that A) they're eminently searchable (whether in print or on the Web) and B) easy to conceptualize as belonging to an imagined "monster kingdom" in the secondary world. But it's difficult to accomplish the latter when you're trying to avoid situating the monsters in a particular secondary world.

That is, I didn't want the conceptualization of demons and angels in OSR+ to depend on some convoluted lore from any particular campaign setting. Consider D&D's legacy of demons and devils or angels across its various editions: almost none of it has a parallel in anything biblical, for reasons variously fictional and commercial. Thus wherever possible, I try to take monsters that have been reflavored by D&D et al over the years back to their mythological origins. For example, instead of the Gorgon being represented as a ox with petrifying breath (likely because of Gygax's predilection for the estoeric), it's presented as what it actually is in Greek mythology—the "species" of the Medusa.

And there's admittedly nothing innovative about that: I'm just trying to keep things pure.

All of this to say, I landed on two simple taxonomies for categorizing all the monsters in the game:

• Seven fixed monster types, mechanical in nature, which each confer abilities to all monsters in the type. Monsters can belong to more than one type.
• A series of tags that help group monsters by their fictional qualities for the purpose of utility: Divine, Fey, Draconic, Insectoid, Cthuloid, Prehistoric, Ectoplasmic, Folk, Demonic, Aquatic, and so on. So if you're looking for an "Undead Arcane Familiar," maybe an Animated Hand is for you.

The Seven Monster Types

These are my sacred seven categories.

I challenge you to find a monster we can't slot into one or two or the types below.

Let's practice:

• Dragons, Coatls, and Unicorns? Cryptids.
• Vampires? Undead Humanoids. Ghosts? Astral Undead.
• Giants, Dryads, or Catfolk? Some are big and some are small, but they're all Humanoids.
• Golems and Animated Armor are Constructs, as are Clockwerk monsters and some Oozes.
• And let's not forget H.P. Lovecraft's array of Eldritch creations, such as Shoggoth, Men of Leng, and Elder Things.

So What's Next?

Identifying which monsters are iconic and worth including was an exhausting process, but it's only the first step in creating a bestiary for OSR+.

Next, we have to write their abilities in such a way that they're modular. This way, you as the GM can mix and match abilities to create your own monsters with the Monster Maker.

This and more in a future installment of Building a Bestiary...