We're finally to one of the best parts of the Arduin Grimoire: the monsters. Each monster is given hit dice (often a range of possible hit dice), Speed in inches, Dec score, number appearing, % Liar, attacks/damage and a few lines of description. I wasn't kidding about % Liar, the "% in Lair" stat was misspelled in OD&D and Hargrave just went with it. So here are the monsters.
Air Shark - Big ol's sharks that swim through the air. They float by means of internal hydrogen bladders, so when killed they go up like the Hindenburg.
Blue Bellower - Really loud giant beetles with shiny carapaces that reflect lightning bolts.
Boogie Man - an undead jerk that turns its victims into shadows, dig the creepy illo:
Deodanth - Described as "tall ebon humanoids with flaming red eyes". Pretty badass in a fight. Are these from a book I've never read?
Doomguard - animated suits of black platemail that do normal weapon damage plus d10 Str points per hit
Emerald Ooze - high power attack slime, gets d8 pseudopod attacks per round, each does 4d10 damage and turns survivors into fellow Emerald Oozes.
Ghost Crab - giant ass undead crabs that drain levels when they catch you in their claws
Grey Horror - giant scorpions as big as your house; their stinger venom paralyzes unless you're a hobbit, then you melt
Hell Horse - undead horse, they hate dwarves and always attack them
Hell Maiden - skull-faced valkyries, totally metal
Hell Star - kinda like a giant will-o-wisp, envelopes you then you go blind plus lose 3 levels per round
Ibathene - a giant one-eyed lizard-beast beast up to 120' long and 50 hit dice in size, Hargrave notes their tongue can lift a fully armored man on horse and their claws can snatch up 6 dudes at one go, can fight for d20 rounds after death due to utter stupidity
Knoblins - half goblin/half kobold "and a smidgen of bat"
Kobbits - kobold/hobbit hybrids, they love scones
Maggoth - imagine if purple worms were maggots and the earth was a giant corpse
Morghoul - like a ghoul but more so, their claws paralyze but their bites cause rotting
Phraint - one of Arduins signature humanoid species, these guys are 9' tall mantis/ant warriors
Red Fangs - giant leaping spiders, their poison is deadly except for elves who are paralyzed instead, these guy love the taste of hobbit so they always attack the wee bastards first
Saurig - lizardmen who are "100% unslowable but are highly susceptible to sleep spells"
Skyray - looks like an aerial manta, but is actually a deadly fungoid lifeform
Spiga - intelligent spiders made of metal
Teng - 4" to 7" long beetles with arrow-shaped head, these guys appear in swarms of up to 10,000
The Helltide - a swarm of thousands of 6" to 9" long ants
Thermite - giant termites that are on fire
Thunderbunnies - rabid jackrabbits appearing in hordes of up to 100,000 members
Seriously, without clever play or powerful magic there's nothing preventing the above three horde monsters (Teng, Helltide, Thunderbunnies) from killing the whole party and destroying a repectable chunk of your campaign setting.
Tryvern - a wyvern with three heads and three tails
Vroat - one of my favorites, basically a giant toad with the head of a crocodile, it leaps at you then eats your head
Wyvergon - fat wingless wyvern that breathes petrification gas
Yellow Peril - less racist than it sounds: an amber-hued giant snake that spits acid
and some new golems - Silver, Gold, Mithril, Adamantine, Orichalcum, Shadow and Light. The Adamantine variety has a disintegration beam.
Next time I'll tackle Hargrave's ideas for hell and the demaniacal inhabitants thereof.