Monster Design and Necessity

So D&D 5E is about to put out a new monster manual... Volo's Guide to Monsters  it might be awful, and it might be really cool.  It sounds like they are focusing more on unreliable narrators and ecology to tell a lot more detail about the monsters in the book, rather then just provide a cacophony of statistics.  Now I fear Volo's Guide will not amuse me, though it is definitely taking cues from Patrick Stuart and Scrap Princesses "Fire on the velvet Horizon", but only because I don't think Elminster flavor text can be anything but dreadful.

Arthur Rackham
(because one needs better goblins)

Still there are things to be said about monster design, and I agree with Mike Merles and 5E when they want to focus on the intangibles of their monsters: their behaviors, ecology, hooks related to them and similar inspirational information for the GM - up to a point.  Monsters are iconic and a central theme to table top fantasy, and doing them well goes a long way towards doing a game well.  The issue is - what's really useful and necessary in a monster design, especially one published as a supplement.  For this I think to the games I've played recently and what makes encounters in them good.

I'm been playing in Ben of "Marazin's Garden's" Dreamlands game a bit and I have noticed that one of the things I enjoy is that we've yet to encounter any monster from a book, at least as far as description and characterization goes.  To me this is a mark of a good campaign and good world building. 

Using unique monsters means among other things that the GM needs to describe them and that the players need to think about them as more then a reference to a Monster Manual.  One of my major complaints about published modules, and even the 5E Monster Manual, is a lack of description for monsters, beyond dull formalities.  There is a balance in designing pre-made monsters, somewhere between several pages of (likely dull with Elminster invoked) of genre fiction the Volo's Guide promises and the terse statistics based descriptions found in the Little Brown Books. I'm not sure where exactly it lies, certainly Fire on the Velvet Horizon is pretty lyrical in its monster descriptions, but its a fun read because its descriptions are full of evocative detail that gets a GM thinking about how to use the monsters described within - and of course anything done well is better then the best thing done badly.

Personally however I have little use for Monster Manuals, even good ones.  For me, the aesthetics of monsters aren't hard to think up and design, and the most important element about an encounter is that it makes sense in the setting.  I tend to run non-standard settings, and making monsters that fit those settings, tell stories about the setting and generally provide a point for player interaction, wonder and decision making is often far easier then fitting monsters from other sources into a non-standard setting.


MANAGING UNIQUE MONSTERS
Every monster in the Dreamlands in unique: molerat men, weird slime people, root kings, a multi-armed something with a a big hungry mouth.  This is wonderful - as a player one must use one's own estimates of what looks dangerous, what might be friendly and what special attacks or defenses a creature might have.  In making these tactical decisions the player is engaging in thinking about the setting fiction rather then trying to remember what the statistics of a goblin or troll are in the latest monster manual, or what some other well known fantasy beast might do. 

Now Dreamlands, isn't using Pathfinder or even Fifth Edition D&D, and designing monsters with statistics for Basic D&D is not mechanically difficult, though thinking up interesting special abilities using very limited rule-sets can be.  However, it's far easier to simply reskin existing monsters and use their statistics, adding or subtracting special abilities and "tricks" as necessary, and one can manage this trick in almost any system. 

Moreover, reskinning and inventing monsters makes a GM notice something - that really there aren't that many stat-lines or 'types' of monsters the players face.

WHAT'S NECESSARY FOR PLAY

What makes foes distinctive is either their place in the game world (how the players can interact with them as NPCs), their descriptions, and sometimes unique abilities or 'tricks' that make combat with them interesting.  Taking a look at the Little Brown Book's, which I believe contain the first tabletop game Monster Manual (and which I've slowly been going through thinking about the monsters within) one notices that the monsters described within are often very very similar.

Don't make me do all the work

For example the "Level 1" table for random encounter on pg. 10 of "Underworld & Wilderness Adventures" lists 8 possible encounters that are the weakest sort of random encounters.  Referencing "Monsters and Treasure" and making some guess for the monsters not specifically listed (centipedes, spiders and giant rats are "Small Animals or Insects" with 1 HP and AC 8) one discovers that 1st level parties will likely encounter a fair number of:

1 - Kobalds (Weak/Intelligent)
2 - Goblins (Weak/Intelligent)
3- Skeletons (Weak or Normal/Intelligent?)
4 - Orcs (Normal Intelligent)
5- Giant Rats (V. Weak/Animal)
6 - Centipedes (V. Weak/Animal - Special: poison)
5 - Bandits (Normal Intelligent)
6 - Spiders (V. Weak/Animal - Special: poison)

One can break these into a few categories, even with some minor variation.  A) Weak intelligent Combatants B) Normal Intelligent Combatants C) Very Weak Animals, some maybe with a special attack in the form of poison.

Monster Strength is broken into three categories: The very weak, generally AC 8 and with 1 HP each.  The Weak with 1/2 HD or 1-1 HD and AC 6 or 7 (Averaging 2 HP each under OD&D rules) and the Normal, who are roughly equivalent to a badly equipped 1st level fighter with AC 6 or 7 and 1 HD (3 HP on average).  Let's assume that there are two other categories of monsters that appear when the dungeon gets more dangerous: Strong (2HD and/or AC 5 or 4) and Very Strong (4 HD and/or AC 3 or 2).  Strong and Very Strong monsters are contemplated in the Little Brown Books, as even on the first level of the dungeon there is a chance of meeting (lone presumably) wraiths, ogres and 6th level fighters.

Obviously as one goes deeper into the dungeon these monsters increase in Hit Dice, but the progression makes a reasonable amount of sense.  For a 4th level party Weak monsters would be 2HD creatures, while Very Strong enemies might have somewhere close to 16HD.  This is even reflected in "Underworld & Wilderness Adventures" with subsequent levels of the dungeon encounter tables containing creatures in the ranges described.

Behaviorally the monsters on the Level 1 table are also quite similar - all of the intelligent ones (goblins, kobalds, bandits and orcs) are going to act in a quasi-militaristic manner, but might be open to negotiation.  Skeletons may fall into this category as well, though they might fit in better with the animal attackers depending on how the undead are treated in the game world.  All the rest will act with animal intelligence and while perhaps less likely to attack initially are also impossible to reason with.

The Little Brown Books are a bit unclear on the number of monsters appearing, seeming to disregard the numbers listed in Monsters & Treasure for some indeterminate lower number based on party size in "Underworld & Wilderness Adventures".  Monster numbers though are a key element to monster design, as larger numbers of attackers, even weak ones, are far more dangerous due to the number of actions they can take.  This is more true in OD&D then in a lot of later editions, and it is interesting to note that the No. Appearing descriptions in "Monsters and Treasure" tend to be high, with 30-300 often listed for humanoids. 

The last element of the mechanics of monster design is a foe's special abilities.  While the list above shouldn't have any special abilities I have included the poison ability for centipedes and spiders out of a desire to have at least some variation in the encounter list.  Poison is a nasty special ability, but there are plenty of other "tricks" monsters can have (breath weapons, spell casting, weapon immunity, a lot of attacks, regeneration - etc.), and offering the players chances to learn and adapt to these abilities (or guessing them prior to an encounter) is one way to make monster encounters more fun and interesting.

Still these four elements (Type/Strength), Intelligence, Number and Special Abilities can mechanically define pretty much all monsters.  Below I have created a set of tables for generating the mechanical elements of a random encounter table. One can roll a smaller die for generally less powerful monsters, and roll separately in each column (Though I'd suggest adding 1 point to the 'Number' roll  for every class of monster stronger then Very Weak, i.e. 1D12+4 for Very Strong monsters). I'd also limit the 'Special Ability' rolls to no more then 1/2 the monsters in a random table, especially for lower level areas.

	Type	Intelligence	Number	Special Abilities
1	V. Weak	None	Swarm (6D6)	Poison (Save or Die)
2	V. Weak	Intelligent	Mob (4D6)	Stealth (Surprise on 1-4/backstab)
3	V. Weak	Animal	Gang (3D6)	Strong Attack (double damage)
4	Weak	Intelligent	Gang (3D6)	Multi Attack (Additional Attacks)
5	Weak	Animal	Family (1D6/2)	Stunning (Save v. Paralysis)
6	Weak	Animal	Pack (1D6)	Entangling (Auto hit after first)
7	Normal	Animal	Pack (1D6)	Immunity (Weapons or spells)
8	Normal	Intelligent	Pair (1D6/3)	Damage Absorption (-X damage per hit/rnd)
9	Normal	Intelligent	Family (1D6/2)	Regeneration (Recovers HP per/rnd)
10	Strong	None	Pair (1D6/3)	Death Ray/Touch (Save v. Paralysis or death)
11	Strong	Intelligent	Solo	Spellcaster (Spell power based on Type)
12	V. Strong	Animal	Solo	Breath Attack (Dam = HP to all in area)

How does this work?  Let's say I'm generating a new area - so I roll up six monster types using the above table and get the following (I used a 6 in 12 chance of monsters having a special ability, with 3 abilities max for the table).

D6	Random, Random Encounter Table
1	Weak, Intelligent, Pack, Regeneration
2	Normal, Animal, Family, None
3	V. Weak, Animal, Pair,  Death Ray
4	V. Weak, Animal, Gang, Stunning
5	V. Weak,  None, Swarm - None
6	Weak, Intelligent, Pair - None

So here we have (based on as close an approximation as I can think of using standard monsters): Goblins (regenerating ones), Wolves, Spitting Cobras, Fire Beetles, Rat Swarm, Kobalds.  Without discussing how uninspiring this monster list is for a GM, it is also an eclectic mess at worst and at best tells the player nothing about the location they are exploring.  The monsters are also likely well known "It's a spitting cobra, I cover my eyes and we throw oil bombs" and their tricks and dangers surmounted by rote memorization of the Monster Manual or other popular fantasy sources rather then through thinking about the description provided by the GM. 

Once one accepts that monsters themselves aren't mechanically especially different (one may still adjust a stat line here and there), but instead falling into broad classes it becomes far easier to use them organically or naturalistically.  Freed from the tyranny of a Monster Manual, where one has a selection of nearly identical humanoids or beasts of the 'Weak' type (goblins etc) that need to be slotted into a location based on what might fit the best, one can take the stat-line of a 'goblin', maybe adding a few touches for flair, and build a unique creature over the mechanical frame.  Such a random encounter list, which might seemed eclectic and thrown together can work to support the feeling of the adventure and location (and might even inspire rooms and challenges - for example I now know there's going to be creepy rodent shrines and rooms of rat sized crypts built into the walls of the location described below).

D&D 5e I think

Now, lets say I think about the area with the above random encounter table and decide it's an ancient crumbling mansion, the equivalent of a Lvl 2 dungeon.  The old place has been cursed by the 'Lues Rex' - the rat deity of disease, poverty and riot as a temple for his cult and locus of his intrusion into the world.  The monsters within are thus going to be manifestations and servants of this rat god, allowing me to take the mechanics above and create a flavorsome list of monsters.

D6	The Verminous Manse - Random Encounters
1	Ratkin (1d6) - Twisted by magical disease, these shaggy lumpen figures with the faces of snarling rats were once men, but their terrible devotion has transformed them.  They attack wearing ragged hides and wielding rusting weapons.  The sorcery that has warped them makes them very hard to kill. HD 1*, AC 6, ATK 1 (weapon/thrown weapon), ML 8, SV F1 *Regenerate 2 HP per round, unless burnt or blessed by a cleric after 'death'.
2	Dire Rats (1D6/2) - Huge filthy Rats the size of a large dog.  They stalk and leap having grown fat and canny on the flesh of their smaller kin and the occasional intruder.   HD 2, AC 6, ATK 1 (bite), ML 8, SV F2
3	Rat King (1D6/3) - A tangle of cannibal rodents, living, dead and undead, twined by thier tails.  These horrors are blessed harbringers of the Lues Rex, the Great Rat King, and share his power and ability to curse and spread death, but their wretched protean forms are quite fragile and they are animated only by simple verminous minds. HD 1-1, AC 8, ATK 1* (Gaze of Filth), ML 10, SV F 0 * The fixed gaze of the rat king produces disease and corruption at an incredible rate.  Each round it may gaze upon a target who must save v. poison or collapse dying and bursting with unnatural diseases.
4	Rodent Revenants (3D6) - Ghostly scuttling rodents, rags of skin and bone, once the great grey eminences of their packs and clans they still serve the Lues Rex, hunting and scuttling among detritus to paralyze the enemies of rodent kind with their arcane bite, leaving them as meat for their multitude of progeny.  HD 1-1, AC 8, ATK 1* (Paralyzing Bite), ML 10, SV F 0 * The bite of these undead rats causes a terrible itching and fever, requiring a save vs. paralysis to resist.  Those who fail to save fall to the floor scratching them selves and delusional for 1D6 turns as the fever burns out.
5	Frenzied Rats (swarm) - A mass of swarming biting rats driven into driven to divine ecstasy to seethe through walls, burst from drains or holes and devour all living things. HD 1/2 (HP 36), AC 8, ATK 2*, ML 12, SV F0  * The Swarm may engulf up to two targets in melee, after an initial hit the swarm will continue to do damage each round until it is destroyed or the target is engulfed in flame or submerged in liquid.
6	Cult Scions (1D6/3) - Men and women with the same sharp cast to their features, the incestuous and mad scions of the Manse, they now serve the rats within catering to their needs and performing the minor interactions with the outside world required by their rodent masters.  They wear concealed armor beneath musty and antiquated clothes and fight with thrown knives and their sharp filed teeth. HD 1*, AC 6, ATK 1 (bite/thrown weapon), ML 8, SV F1