Thanks to the warning colors of their exoskeletons and their venom-dripping fangs, people know better than to disturb the arachniida, although caution only helps to a point: The many-legged creatures are often content to feed on less intelligent bugs but waste no occasion to attack prey that stumbles upon their nests or disturbs their webbings.

Arachniida range from smaller than a hand to as big as a cave, with a wicked intellect shining through their multiple eyes well beyond the dangerous cunning other predatory bugs possess. They communicate through an elaborate language (one Scarabs can learn to speak) and demonstrate an unsettling aptitude for problem-solving and the use of tools. Some gastrevores theorize that arachniida are rapidly evolving in response to the settlers’ invasion of their territory. The implication is that in a handful of generations, they’ll become a menace nobody will be equipped to stop.

A host of different species tied together by shared characteristics, the arthri are armored bugs whose body develops length-wise, a pair of legs carrying each segment forward. Seemingly never-ending hunger and the instinct to dig bind them together in common purpose, as does the violent frenzy they fall into whenever their tunneling efforts are thwarted or hindered, either by a misplaced trap or an inauspicious cave-in.

Small arthri amount more to vermin than threat, always eager to devour a settlement’s food stocks. Flames keep them away without much trouble. Bigger arthri are a different matter, with colossal ones being true calamities for whoever happens to be on their path. Arthri play a central role in the World Below’s ecosystem, chewing on refuse, toxic fungi, and bodies alike, but their diet includes anything their mandibles manage to grasp, people and houses included. Hunting an arthri for its armor plates leads more hunters into the beasts’ gullet than to a triumphant return.

Chimericals are aberrant creatures made of several other creature’s body parts, with no shared traits save for their unknown origin, their hatred for all beings, and their savage territoriality. Scholars wondered for generations whether chimericals come to be because of the influence of Kaos or whether something out there cuts and sews them together before releasing them against the world, but an explanation would change little.

Although only the most isolated caves contain chimericals, these beasts are the sort that adventurous types seek out for the glory of slaying. Chimericals eradicate all life inside their lairs and wait for bold heroes to walk into their territory, at which point the hunt is afoot. Only one will leave alive. Chimerical offer only hatred and violence.

An oddity raising uncanny questions about the boundaries between settlers and insects, chitters keep more communities under their heel than scholars like to contemplate. Although it’s unclear whether they started as insects who evolved in response to the makiru expansion in the World Below or explorers who left behind their nature to become insectoid predators, chitters are clever, malicious, and lethal.

With thick skin and sharp mandibles, a chitter pack makes for a deadly foe, but the creatures feast and prosper thanks to their cunning more than their might. Chitters look for isolated settlements without allies and circle them, terrorizing the inhabitants with showy assaults, and establish a gruesome ecosystem where the humanoids live as cattle for harvesting.

Chitters take care of their “herd,” happy to defend their stock from danger and let people come and go as their lives demand, but at the same time reserve the right to slaughter anyone. Whoever reveals the settlement’s secret or rebels is taken care of like a sick beast endangering its kin. The chitters force the survivors to live in a nightmare where everyone prays to not be the next in line to feed their monstrous masters.

More a natural disaster than a living species, churnians are the kind of encounter all tunnel explorers hope to avoid. Unlike many other creatures in the World Below, churnians demonstrate a single point of origin — the Obscura structure of the Churn — but spread across the underworld with ease thanks to their speed. While the creatures’ biology indicates they came from somewhere else, a lightless plane where their eyeless bodies would feel right at home, the churnians’ bloodthirsty, taciturn attitude prevents more than conjecture.

Churnians use echolocation to fly around tunnels, an evolutionary tool they manifest as horrid shrieks and howling screams. The horrors move at such an absurd velocity their screams rival windward gales in intensity and strength, while the eldest can turn invisible.

Churnians found in the rest of the World Below sprint from place to place, ripping apart everything they encounter. Scholars know only frustration when it comes to churnians, even ignoring whether the monsters are mere animals or a species with a culture. The yaggyakh demonstrate remarkable knowledge of the monsters’ weaknesses, betraying a history they refuse to share, and the churnians give the tekeli-li wider berth than anything else in the underworld. No other clues exist about the Churn-spawned species’ true nature.

Darklings are a curse, not a people, say some. They are the fear of the Dark made manifest, the embodiment of what happens to those who find themselves alone in the shadows and let the inky blackness in. Legions of darklings inhabit the World Below’s darkest corners, but each cave — each settlement — has places where light doesn’t shine. Here, darkling packs wait patiently, folded into tight crevices and remote nooks, coming out in droves whenever someone approaches.

Darklings take delight in tormenting their victims, whispering threats and laughing from the shadows until they decide the game has lasted long enough. Darklings tasted the darkness and were consumed by it, now existing as carriers of this black waste, for when you cut a darkling open, a slick of liquid black seeps from its body and blots out even the light of Kaos rock. It burns the skin, blinds the eyes, and can make others into darklings, its touch being the last thing all darklings’ victims feel.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Generals and proud conquerors, ruby dragons inhabit the intermediate strata, although some travel skyward or wellward to satisfy the urge to expand. Ruby dragons crave the increase of their temporal power, subjugating entire populations and keeping them bound under crimson claws. These dragons consider stories about triumphant humanoid warlords as a provocation and seek out the most heralded of tyrants to subjugate or destroy, as befit their whims.

A ruby dragon’s entire body resembles a jagged construct of scarlet and crimson gems. The smell of ozone surrounds them while hints of sparks and lightning shine within the rubies, suggesting the electric core of the creatures’ being.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Scholars, intellectuals, and keepers of secrets, sapphire dragons appear in legends told seaward and windward, but their thirst for knowledge leads them wherever mysteries need solving. While sapphire dragons are less inimical to outsiders than other dragons, wise settlers learn not to mistake their indifference for kindness: sapphire dragons care about learning the mechanisms of the world, gathering lore with little scruples about whatever it takes to obtain it. They despise whoever refuses to share knowledge while requesting hefty payments or services to unveil theirs. They hate the guilds for their hoarding of information despite sharing that desire to lock away their considerable knowledge.

The sapphire dragon’s blue, bejeweled body exudes an aura of cold, covering their smooth skin with frost and rime. A vivid azure energy pulsates within, like light stolen from the purest ice caves.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Custodians, gardeners, and furious guardians, emerald dragons reside wherever life thrives in the blind depths of the underground. Emerald dragons elect themselves as protectors of the natural world, but their mission manifests as violent possessiveness, where the creatures unleash unbridled rage at whoever dares touch animals or plants they protect. They are deaf to any prayer for food and medicines. Entire settlements starve after emerald dragons cut them from their nourishment, while more calculating emeralds are known to kidnap specimens and imprison them as provisions to feed to their own people.

The emerald dragon’s elongated shape resembles a living viridian machine, shining like a gem holding the secrets of life itself within. Even earth responds to the creatures’ majesty, shifting and brimming with energy under their steps. Their breath attacks emerge as a corrosive spew coating everything before them.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Devourers, destroyers, and eternal wraiths for which life and death have lost any meaning, fossil dragons haunt darkward caves where even specters and undead hesitate to venture. Not even fossil dragons know for sure whether their lineage fell to a curse or made a conscious decision to transcend mortality, but they now exist as something neither wholly dead nor alive. Blessed — or condemned — to twisted immortality, fossil dragons must devour the life of other creatures to preserve their own, otherwise their souls abandon their bodies until circumstances enable a resurrection.

Fossil dragons resemble grotesque frameworks of ancient bone and stone. Black streams flow from their empty eye sockets, while clouds of dust and darkness wheeze out of their joints with each slow, solemn step. Their breath attack emerges as a cloud of rapidly hardening salt and sand.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Covetous fiends, gold dragons rule over lower strata where lava and sparkling veins of precious metal emerge from the earth like rivers. More than any other of their kin, gold dragons enjoy their solitude, if only because most believe other creatures crave their treasures. The gold dragons’ paranoia encourages them to carry their hoard along as they burrow through the ground, melting their treasures into their skin with their fiery breath and letting it cool into glistening, impervious armor.

A gold dragon’s body looks like a bulky mass of molten stone and metals, forged into magnificent horns and intricate ornaments to glorify their bearer’s appearance. Fiery magma rivers cut through their mantle, smoldering beneath at points while erupting in others.

Among the mightiest creatures of the tunnels, dragons are presences that no settlement can ignore. Be they merciless overlords, solitary monsters, or enigmatic hermits, dragons imbue the land around them with their own brand of power, drawn from Kaos and processed through the crucible of their being.

While their personalities vary, dragons are driven by pride, desire, and an aspiration to a magnificence lesser mortals cannot comprehend. Their morality sometimes seems to align with that of other creatures, but it exists in a different paradigm. A dragon can act as patron for a settlement while being a winged bearer of destruction for another, but each demands respect, if not outright worship. Meanwhile, plenty of dragons outright refuse to entertain conversation with non-dragons.

Although dragons consider the reminder a heinous offense, most of them are foreigners to the World Below. They have Dialectics of their own, although they consider those of others as disgusting aberrations. The environment of a dragon’s lair takes after its master, changing according to the shape of their Dialectic.

Mad oracles, cataclysms, and Kaos given monstrous shape, diamond dragons exist wellward. The mightiest of their kind, diamond dragons drank deep from the Well and were forever changed. Their minds became unbound by the revelations they experienced, while their touch warps blessings and aberrant mutations into being in equal measure. To the eyes of everyone — other dragons included — diamond dragons are dangerous- ly wild. In truth, their perception uplifts them to insights only the Well Liches can match. Diamond dragons follow their own cryptic whims, their chaotic reactions and random impulses guiding them through the World Below.

Kaos burns within diamond dragons. No diamond dragon looks like another, but their crystalline shape shines in a myriad of colors, some not of this world. Pure and pristine yet utterly alien, diamond dragons bleed Kaos into the air. The ground it- self mutates beneath them, and the light cutting through their prismatic shapes stabs fragments of distant realities into sur- faces, objects, and flesh. Their breath attack manifests as a blast of pure, gleaming, liquid Kaos.