Monday, February 24, 2020

d66/d18 Flails

Image result for flail striking over a shield

You should look at Mork Borg if you don't already know about it; it was because of a Twitter exchange with them that I've thrown together this table of random flails.

Bear in mind, the flail familiar to us from consumable media is not necessarily a replicable historical object (see The Curious Case of the Weapon That Didn't Exist* and The Case Against the Medieval Ball and Chain).

I'm not an expert, nor a mall ninja, so I'm not making any claims to historicity, to realism or to simulationism.

Flails in Game.
  • will have a feature like Awkward, Clumsy, Heavy or even all three
  • primary special: ignore shields (flails strike over or round them)
  • optional/secondary special: chains can be used to snare & disarm 
  • on a fumble, you definitely hit yourself

1st d6 (1-2) 2nd d6:

  1. Death Tolls Twice: double-ended flail; wield it like a quarterstaff, if your Strength is 15+.
  2. Whirligig: triple-headed throwing flail; whirl to wind it up, then hit the release.
  3. Flagellant’s Friend: three slungshot on a rod; subdual damage.
  4. Flagellant’s Favourite: nine hooked chains on a haft.
  5. Flagellant’s Fine Fellow: spiked iron paddle on a short chain, heated red hot; stout, two-handed haft.
  6. Star of Dawn: not a morning star.

1st d6 (3-4) 2nd d6:

  1. Hunter’s Belt: not a triple-headed morning star.
  2. Goddess of Love: not a morning star with a hollow head for burning sulphur; three-headed version is The Triple Goddess.
  3. Tresses of Medusa: three, six or nine chains on a haft; spiked balls are hollow as venom reservoirs.
  4. Throne of Skulls: triple-headed skull flail with spring-loaded snapping jaws.
  5. Dragon’s Neck: flanged/spiked head on a telescopic chain; reach weapon or actual hookshot-from-Zelda, depending on your campaign.
  6. Meteor Hammer: double-headed long fighting chain; flanged/spiked heads forged of starmetal/meteoric iron; cage heads for combustible material.

1st d6 (5-6) 2nd d6:

  1. Ogre’s Choice: 3+ sword/axe blades on short chains; two-handed haft, Str 15+ to wield. Stupid idea; looks intimidating.
  2. Murther of Crows: double- or triple-headed straight-bladed sickle flail; two-handed haft.
  3. Gentleman’s Flail: bafflingly petite quadruple-headed spiked flail; hollow handle for drinky-poos or secret notes from/to your beloved.
  4. Shooting Star: unassuming single-headed one-handed flail with a pistol built into the haft.
  5. Shield Splitter: enormous two-handed single-headed spiked flail, Str 15+ to wield; anytime a shield foils an attack from this, it has to save vs. crushing blow.
  6. People’s Friend: repurposed agricultural flail; studded with nails; dipped in shit.

*The Weapon That Didn't Exist.

  • Only available in post-medieval time periods, this is an apparently ordinary flail, morning star or chain weapon.
  • Once claimed, it can only be relinquished on your death or by a quest, remove curse or similar.
  • It does not exist, has no encumbrance value and is completely undetectable except when you are wielding it in combat; it is always your primary melee weapon and appears in your hand. You can still wield other weapons in your off-hand.
  • If you attempt to put it down or pass it to someone else, it vanishes until you next wield it in combat.
  • If you are disarmed, it vanishes as it leaves your grip but will be in hand at the start of the next combat round.
Edit: Table removed for wider browser compatibility.





Wednesday, February 12, 2020

Rangers are Bugbears and/or Halflings

Here are two different Rangers for Old School D&D adjacent games [edit: three, there's two Bugbear Rangers]. They owe a debt to two posts, both from B/X Blackrazor. The first I've already linked to in my recent post on halflings. The second, I just read yesterday and it helped condense some Ranger-based thoughts brought on by finding out about the pioneer sergeant/assault pioneers (beards, axes, clearing the way ahead).

Image result for coldstream guards pioneer sergeant

None of these gets any spell-casting ability; that's on you if that's what you need.

[edit: Sorry they're not actually Halflings or Bugbears, either; that's also on you if that's what you need]

Old School Ranger as Halfling.


Halflings are stealthy, swift and hardy, so are Rangers.
  • Use the Halfling class, but call it a Ranger. That's it. 
  • AC bonus vs. larger-than-human covers AD&D 1e/2e bonuses vs. 'giant-class'/favoured enemy.
  • Missile and Initiative bonuses are Ranger appropriate.
  • Outdoor stealth is a no-brainer.
  • Armour choices map to AD&D 1e.
  • Weapon restrictions would fit with the environment of crowded trees and tangled undergrowth.

Further Elaboration (untested).

  • Use Cleric or Thief saves instead, to offset the following.
  • Give 2d6D1 hp at 1st level.
  • Track as find secret doors/traps (or INT/WIS check).
  • No XP bonus for high Ability Scores.

Old School Ranger as Bugbear.


(The B/X Blackrazor post explains what I mean better than me re-hashing it)

A bit more difficult, as there isn't a core class that can be directly reskinned.

Dwarf Hack (untested).

  • Use the Dwarf class as the base, but regular Fighter saves.
  • Feature swap: instead of infravision, they get the Bugbear's ability to surprise 1-3 on d6.
  • Feature swap: instead of languages, they get 2d8D1 hp at 1st level.
  • Feature swap: instead of detection, they can track 1-2 on d6.
  • Same reasons for their weapon restrictions as Old School Ranger as Halfling.

Orcs of Thar Bugbear Hack (untested).

  • Use the Bugbear class as the base.
  • Do not apply Ability Score adjustments at chargen.
  • Do not use negative XP levels (Youngster, Teenager).
  • No infravision.
  • Surprise 1-3 on d6.
  • Start with 3d8+1 hp; no additional hp at 3rd & 7th level.
  • Tracks as find secret doors/traps (or INT/WIS check).
  • No XP bonus for high Ability Scores.


Commentary.


Rural folk hero, incognito king, brutal forester, unsociable monster hunter, practical bandit, hippy with a bow...

The Ranger is one of my all-time favourite* D&D classes (more accurately 1e/2e AD&D), and one that was conspicuously missing from the archetypes presented to me in my earliest game materials (the version in MERP didn't inspire much, but that was for me a wider problem with the setting and system).

1e Ranger was interesting; 2e was more like how I thought a Ranger should/would be (dual-wielding seemed right, though I wasn't aware of the influence of Drizzt Do'Urden on this). The modified Ranger of 1e Lankhmar setting, attaching to Fafhrd and assorted berserkers, and lacking alignment constraints, was a stepping stone between the two. 

My conception of the ranger was influenced more by reading the statblocks in White Dwarf, the brief description in What Is Dungeons & Dragons?, and hot-pants-and-face-like-a-crumpled-apple Aragorn of Ralph Bakshi's LOTR (first voice crush was likely John Hurt, though could just as easily be from Watership Down), than it was by what was intended in 1e AD&D. 

This conception has been updated since I came off ttrpg hiatus.


* My favourite is multi-class Fighter/Druid.










Wednesday, February 5, 2020

Abstract Hit Points and the Casualty Table.

If you're not familiar with at least some of the various arguments, controversies and problems D&D-adjacent, inflationary hit points raise, or you want a refresher, top of Google is The Alexandrian; a bit further down and more recently (it still goes on), Kabouter Games with Gygax quotes and (oh!) a link to The Alexandrian as well. And this at Mythlands of Erce from in between.

I'm assuming combat or at least bodily injury are going to be aspects of the game I make/play; at the moment, I'm using Hit Dice and hit points to keep track of wounds in and out of combat for familiarity/ease of use.

One of the first D&D adjacent 'fixes' I can remember thinking about was how to make 1st level characters less squishy; particularly the magic-user and thief. I'm not so old school that my first introduction to ttrpg wasn't framed as hero-on-a-quest; our alternative personas did not feel disposable, we had somewhat different ideas to Gygax et al about how the game was to be played, and we were not interested enough in system implications and intricacies to see them.

CON hp.


The simplest fix, and one that sprang to mind when I was thinking about mortal, mundane characters surviving in my Stranger Aeons setting, is to give starting characters hit points equal to their Constitution score.

Characters still accumulate Hit Dice as they advance levels, but will only increase their max./total hp once they are able to roll more than their CON. A Mentzer Red Box Fighter might do this by 2nd level (2d8); a corresponding MU or Thief might not do the same until 4th (4d4).

Adjustments for high/low CON can be applied as normal, at your option; the 'extra' hit points are only meant to help the character survive the first phase of the campaign, so it goes back to normal in the end.

The Casualty Table.


The Casualty Table is an alternative to death at 0hp. The spread of 2d6 means that a Serious Wound is a likely outcome, but that's better than instant death, isn't it?

The table's at the end because I kept messing up the formatting of the post.

  • At 0 hp or below, you roll 2d6 and consult the Casualty Table;
  • Casualty = prone, helpless, vulnerable to coup de grace/all hits are critical;
  • Recovery Roll at the end of each round; if you succeed, back to 1 hp at the beginning of the next (3d6 vs. modified CON or just a d6 vs. TN - one or the other);
  • Mortal wound, you need help from someone else to recover;
  • Graze, you automatically recover at the beginning of the next round with at least 1 hit point (roll d6, maybe even with CON mod).

Further Elaboration.

  • Damage in excess of 0 hp means instant death at a certain total. I've seen and used -3 and -10, as well as a total equal to your level. I'm planning to use CON as the threshold.
  • Bleeding Casualties: use the d6 Recovery Roll to determine if you're bleeding; lose 1 hp at the end of each round, and then roll d6 Recovery Roll to see if it stops by itself. Mortal wounds always bleed and do not stop on their own. Recovery Roll and Bleeding rolls are separate.
  • Automatic Recovery Option: either in round 7 or at the end of the encounter; only Mortal Wounds are exempt.
  • CON hp are sort-of your 'body' hp and anything in excess is abstracted (see above).
  • Once you drop below CON hp in an adventure, CON hp becomes your maximum until you properly rest up, recover and reroll your hit points (if applicable). Usually means 'return to town'; some spells, potions, miracles overrule this.
  • Until properly treated, Wounds could either cap your CON hp at a reduced level until properly treated, or could come straight off your CON if you soldier on.

Logical Progression from Abstract hp?

  • Theoretical, planning to try next time I run a one-shot, and assuming only d6 HD.
  • If hp are abstractions, representing things like divine favour, skill at arms, blind luck, stamina, morale etc., then maybe we can use them dynamically? Or, at least HD.
  • Instead of just rolling up a starting pot of hp, expend them for rerolls on the Casualty Table, Recovery Roll or Bleeding rolls: you could do both with enough HD; you already have at least CON hp.
  • Unused HD can be expended in combat to reduce damage taken or after a successful Recovery Roll to roll some new hp so you can jump straight back into the fray.
  • Once used, you only get your HD back through proper rest and recovery, even if you somehow get hp over your CON hp before this.

2d6
Wound
Recovery Roll (3d6)
Bleeding/ Recovery Roll (d6)
Max. Con hp
2
Mortal
help only
help only
3
3-5
Critical
Con -6
6
Con -6
6-8
Serious
Con -3
4+
Con -3
9-11
Light
Con -1
2+
Con -1
12
Graze
automatic
automatic
Con

Friday, January 31, 2020

Ye Olde Halfling

I shouted into the howling abyss about halflings recently and that thread covers the content of this post much more succinctly.

(See also http://bxblackrazor.blogspot.com/2010/09/halfling-love.html from 10 years ago, demonstrating giant killer credentials: I am so late and I cannot keep up)

Because of my own historical anti-Tolkien prejudice (for better or worse, I conjure Fafhrd and Grey Mouser when I think of the basic fantasy adventure set-up) and cleric fetish, I didn't have much time for halflings in any edition or setting. Even the Athasian 'cannibal halflings' weren't as interesting as that sounded (opinion, not fact) when Dark Sun was trailed.

Re-reading old gaming materials, I was struck by a very different halfling to the image I had from fictions and illustrations.

Ye olde halfling (and 'mine' isn't the oldest) already plays well as a monster, if you wipe off the 'hail fellow well met a tankard for my friend and a little something for my pipe'. Forget Tucker's Kobolds: halflings are the Goblins of the Labyrinth, scuttling round Sarah's house.

Mentzer Red Box Player's Manual (my mechanical/statistical first encounter): AC bonus of 2 vs. anything bigger than a human, +1 with any missile, +1 Initiative, 90% undetectable in natural surroundings, 2 in 6 (33%) undetectable in shadows/cover.

90% undetectable! The thief at the same level is 90% detectable and won't ever come close to catching up in most campaigns. Even indoors, this halfling is better at hiding than a thief until around 6th level.

(Incidentally, these abilities don't appear in the monster section entry)

These are ambush predators as much as hide-behinds; these are borderline supernatural powers.

What are the natural surroundings of halflings in your setting?

Image result for the haunting 1999 gif
The Haunting (1999)
(Also, put in your gifs afterwards, so they're not looking at you all the way down the page)

When the Dark Sun setting was trailed, 'cannibal halflings' didn't conjure up big hair and bone knives for me. I could see the comfy hobbit-holes, nice cushions, hearty welcomes...

And the locked pantry. The dark root cellars winding off into the depths of the hill. Feeding you up, insisting you stay. You lay down for a nap in one of the guest bedrooms.

More Parents (1989), maybe, than The Hills Have Eyes (any of them).

Phalse, from Azure Bonds (1988 Forgotten Realms novel), wasn't technically a halfling, but reading his sleep assault on Olive Ruskettle put another shiversome sheen on the hairy-footed ones. I would have been about 12/13, impressionable, and I've never really been able to shake the perception of an inbuilt capacity for creepiness.

Finally, there's a good reason I used the halfling experience table and saving throws as the basis for the Old School Shoggoth Race-as-Class.

IIRC, in both D&D  (Mystara? Blackmoor?) and WFRP there is or was some lore that halflings were created, built for purpose; I think, by the Old Slann, to resist the warping power of Chaos, and by some Immortal-or-other to resist (amongst other things) radiation.

Even if my recollection is faulty, it puts me very much in mind of HPL's Old Ones/Elder Things/Primordial Ones, and their highly resilient manufactured species of slave-machines...

...something I'll return to in a later post, once I've compiled the notes.


Wednesday, January 29, 2020

d66/d18 Gems and their Magical Properties


[Edit 21/06/2021 to replace old table & add pic]

All gems are worth their base value (1 to 18, below) in the common currency unit of my/your setting, multiplied by d6 x 10 or 10d6 (if you prefer).

They are either the size they would be in reality, or they are about the size, shape and colour of the dice you are holding at the time. Or compare them to bird's eggs, quail up to duck.

Gems can be kept as treasure (to be traded for cash and counted towards XP after an adventure) or can be used during an adventure as a one-shot magic item.

Once used, gems shatter, disintegrate or are otherwise destroyed; the remnants are worthless.

If you intend to save a gem to use in a future episode/session of your current adventure, it cannot be counted towards experience even if you later change your mind and trade it for cash (you still get the money). Define the boundaries/unit of 'an adventure' if your game does not already cover this.

You cannot buy gems on the open market to take them into an adventure to use as magic items under normal circumstances. Their magical powers are a property of the condition of 'adventure' and as such do not operate outside of this - they are drained by exposure to the mundane.

Ignore any of this that doesn't fit with the game you want to play.

Roll 2d6:

1st d6 (1 to 2) 2nd d6:

  1. Quartz (1): reroll 1s on any roll, once.
  2. Lapis Lazuli (2): reroll a failed fear/ morale save.
  3. Topaz (3): reroll a failed spell save.
  4. Coral (4): cure wounds at 0 hp.
  5. Turquoise (5): reroll or force a Reaction Roll.
  6. Amethyst (6): reroll a failed Strength roll.

1st d6 (3 to 4) 2nd d6:

  1. Amber (7): reroll a failed Constitution roll.
  2. Carnelian (8): reroll a failed warding, spell casting or attack (melee or missile) roll.
  3. Opal (9): reroll a failed Intelligence or Wisdom roll.
  4. Jacinth (10): reroll fire damage or failed fire save.
  5. Aquamarine (11): cure wounds or doubles effect of your casting.
  6. Jade (12): reroll a failed Dexterity or Charisma roll, or a failed missile attack roll (thrown or device).

1st d6 (5 to 6) 2nd d6:

  1. Serpentine (13): reroll a failed attempt to deceive/ stealth/ steal/ backstab.
  2. Pearl (14): reroll a failed polymorph/ petrification save.
  3. Ruby (15): reverse a failed roll, automatically succeed on a roll, or convert a success to a best possible result.
  4. Sapphire (16): recover a cast spell without penalty.
  5. Diamond (17): protection from damage, or reroll a death save.
  6. Emerald (18): protection from/ dispel magic.

This table is based on the Gem Generator from the UK Corgi paperback edition of Tunnels & Trolls, which is where I first encountered the d66 table.

Monday, January 27, 2020

Easy Encumbrance and Fatigue

(I'll boil this down into a nice, terse table to add after publication)

Basic Assumptions.


  • That you're playing an Old School/D&D adjacent ruleset, with Classic Six compatible Ability Scores rated 3-18 and Armour Class (though damage reduction could be used to stand in for this).
  • That the amount of stuff you carry should have in-game consequences.
  • That you want to model fatigue as one of these consequences.
  • That you're not desperate for extreme granularity or simulation.

Carrying Capacity and Items/Objects Counted.

You can carry as many items/objects as you have points of Strength before you are Encumbered.

Each point of Armour Class from armour worn/carried counts as an item/object.

The basic unit of item/object is the weapon. While this is quite a common basis for simple encumbrance systems, I'm using Dragonwarriors (p.60 of 1985 edition) as my source.

The examples of equivalents those rules give are: full quiver of arrows/bolts, scroll, bottle (potion or wine, presumably), lantern, torch, c. 150 coins. 

I roughly agree with this, though I also suggest a 'three makes an item/object' category which includes scrolls, herbs, jewellery, single dose magic potions, knives (including throwing knives, but possibly not daggers), tinderboxes and so on.

Objects of negligible encumbrance (an individual, high value/magical coin; a gold ring; a magnetised pin; a pinch of bat guano; a quill pen) aren't counted unless you've got an awful lot of them. A rule of thumb might be 10 or 12 to the item/object.

You might allow a stack of 3, 5 or 6 javelins or torches to be an item/object, but I probably wouldn't.

Encumbered/ Tired.

When you are Encumbered, your Dexterity is halved. 

You can put things down in order to climb walls, pick locks and fight monsters, and so go back to normal Dexterity, but otherwise you take the penalties.

A GM could waive the Dexterity penalties for fine motor skill activity, but I personally find being encumbered IRL to make me generally clumsy so I'd stick with it unless there was a particularly good reason not to.

Every time you do something strenuous (jump a chasm, climb a tower, chase the thief, and definitely combat), you will be Tired until you take 10 minutes rest (1 turn) to recover. While you are Tired, all your Ability Scores are at -1.

While you are Encumbered, you can carry further items/objects up to your current Constitution, at which point you are Overburdened.

Overburdened/ Slow.

When you are Overburdened, your Dexterity is 3 and your Strength is halved. This does not effect your overall Carrying Capacity; you were already Encumbered and now you are Overburdened.

When Overburdened you need 30 minutes rest (3 turns) to recover from being Tired due to strenuous activity.

You are also Slowed while Overburdened, and may only act/attack every other combat round and will always be the last to act when you do (or apply the effects of your game's equivalent of a slow spell).

Further Complexity.

Use the modifiers from The Black Hack Additional Things to give unusual objects more impact on Carrying Capacity.

Where you carry your equipment is as important as how much you can. Unless you specify, the top three items on your inventory are easily accessible; the rest will require at least a Dexterity check to retrieve it when under attack/stress. Worn items and your primary weapon are exempt from this.

Using with Tunnels & Trolls.

T&T has uncapped Strength and Constitution, so this system can't just be ported straight over (I'm basing this on the 5th edition rules, as per the UK Corgi paperback - a lot's changed that I haven't followed). As well as the number of item/objects potentially spiralling, the penalty for being Tired becomes insignificant.

Maybe the capacity could be 10 + Level to Encumbered and then same again to Overburdened, or 10 + a bonus worked out by comparing your T&T Str/Con against a D&D modifier table that extends beyond 18, with Tired having the effect of making saving throws one step harder.

I don't know. 

I've not had the opportunity to play or run T&T enough to work through this outside of my own head.

Commentary.

Encumbrance is an intrusion of reality into your gaming space.

Encumbrance is probably the first rule jettisoned when I/we started gaming, even though it is important to a certain kind of play. It should encourage the use of hirelings and pack animals, which can be used to add further drama, risk, social interaction and pathos; these probably weren't concerns to 10-year-olds wanting to load up with imaginary treasure and weapons.

I never liked granular weight-based systems because of the book keeping and not being good at estimating/calculating real weights; I've since come to appreciate how simple the armour + treasure method, revisiting it decades later.

My earliest thoughts on encumbrance were heavily influenced by:

Dragonwarriors and Fighting Fantasy rpg both give 10 as an adventurer's carrying capacity, but it's just a limit - there are no consequences given for exceeding it. 

The Lone Wolf gamebooks also float around this 10 maximum, as you could carry 8 backpack items and 2 weapons (plus unlimited Special Items, eventually reined in to 12). Again, this was a limit; there were no consequences for cheating.

Constitution got included in carrying capacity because of Maelstrom: it doesn't have a Strength stat, but uses Endurance instead to determine the armour you can wear and the amount you can carry.


This is pretty much the same system as I use for my heartbreaker, and it could be bolted onto non-D&D adjacent systems with a little bit of conversion. I'm sure there are lots of other similar systems out there, but this is my particular outcome.






Thursday, January 23, 2020

Elves are Wolves/ Chthonians are Martians

(not mutually exclusive, unless that's what you want)

Elves are wolves, because of predictive text/auto-correct. 


They are grey-haired with an under-bite; pointy ears and eyes that reflect red; subtly pointy teeth; bare arms and no coats/cloaks, even in the deep winter. Dress in dull natural shades, overgrown with leaves, or simple furs. Shorter than humans, but stocky, solid.

Can be mistaken for surly farmhands or rebellious peasants, until you realise they're just waiting for you notice they're not.

Don't like fire and noise (gets them a bit Grendel). Eat an uncooked, omnivorous diet; meat-heavy for effect. Prefer traps to ambush.

Immune to mortal diseases, but can be poisoned. Can cast spells in either form. Can communicate with animals, and often team up with owls (and wolves, unsurprisingly).

Carry and use stone, bronze and copper tools/weapons; iron burns them; steel cuts them just fine.

Elven boots worn by mortals allows stealthy passage through the woods and the snows, and leave a trail of paw prints. An elf instantly knows when a mortal is wearing their boots, and all elves recognise the false trail.

There are no elven cloaks, but hairy elven belts that allow mortals to transform into wolves under the moon (not necessarily full). You need to take your clothes off to transform, and you need both those and the belt to reverse the process.

If you have half-elves, the other half is wolf, not human.

Chthonians are Martians...


...because maybe I misread something in The Jennifer Morgue (Chthonian war machines?).

If you have access to the materials, take a quick look at Chthonians, Lloigor and Flying Polyps (my reference was Call of Cthulhu 5e). I know they're different from each other, but there's also a big strip of 'same' running through them all.

I'm following a line of thought as follows: Chthonians are Martians (but not from Mars); Chthonians are Lloigor are Flying Polyps; Chthonians are also Der(r)o (Shaverian and/or Veins of the Earth rather than D&D).

They're significantly bigger and bulkier than humans, but by no means the giant worms of the source material, with a face full of tentacles and a boneless sac of a body. They might have a roughly frog/toad-like form (because this is still the Mythos); limbs are rudimentary, muscular flaps of hide. Probably no eyes, but clusters of pearly orbs that are mistaken for them (the unfertilised eggs they constantly produce). A bear of most suitable size crossed with a salamander would serve for a stat block in a pinch.

If their habitat is not the molten regions beyond the mantle, it's certainly the hottest and meltiest of the subterranean realms. Low(er) temperatures, volumes of water, and excess of oxygen have deleterious effects on them; they crust over, go into hibernation and dim dreams, and petrify inwards if not recovered by their own kind.

Chthonians are highly technologically advanced. Surface-dwellers (and we'll include most subterraneans in this category, too) have knowledge only of the extensive range used to terrorise and dominate, with domestic appliances being restricted to the deepest, hottest places where no mortal could hope to survive.

All the things that the games say Chthonians, Lloigor and Flying Polyps can do at a distance (draining your energy, trapping you at your desk, flattening a town, horrible nightmares, reptilian manifestations etc), these Chthonians can also do, using machines - either deep beneath or in their carriers.

Chthonian carriers look a bit like the Chthonians you're expecting, but maybe with a three pronged grapple instead of a mess of flailing tentacles; they can stand up and stride about on these, repurposing the rock-melting ray as a weapon and releasing great clouds of rare, poisonous elements.

Unintentionally, Chthonian incursions release bizarre spores from the subterranean realms, which mutate and colonise the surface.

Like the mind flayers want to put out the sun in some editions, the Chthonians ultimately wish to drive the planet into the solar corona at which point they would evolve into magnetic plasma beings. This is their religion, so this could be nonsense.