Role in Its Society:
Tethrix is the unseen toll-keeper of a narrow Underdark gorge where a few flimsy bridges and ledges offer the only crossing for miles. To most denizens, “the Line-Drinker” is half warning, half curse—what you shout at a careless miner when their rope-handling is sloppy.
Duergar and drow patrols know something lives on the gorge wall that steals ropes, hooks helmets, and drags people into the dark. They reroute caravans or post extra crossbowmen when they must cross Tethrix’s span. Goblins and kobolds have turned him into part of their defense strategy: they lead intruders across the bridge, then fall back, trusting Tethrix to snatch the choicest victims.
More sophisticated groups sometimes farm cave fishers for their sticky filament, but Tethrix has resisted domestication. He has escaped broken harnesses, cut chains, and collapsed cages. Even now, a rusted iron collar hangs half-embedded in his chitin—a reminder that he is nobody’s pet.
He isn’t part of a faction, but his presence defines the gorge as contested ground: a place where only the bold, desperate, or well-prepared dare lay a rope.
Appearance Description:
Tethrix resembles a grotesque cross between a crab, a spider, and a piton rack. His body is a low, armored knot of reddish-brown chitin, flattened against the stone. Eight hooked legs splay out around him, each tipped with cruel, barbed claws perfect for anchoring into sheer rock.
A ridged carapace covers his back, mottled with mineral streaks and lichen stains that match the cliff face. The underside is paler, studded with small, twitching sensory hairs that taste air currents and vibrations. At the front, a cluster of black, beadlike eyes glitters above a hooked, proboscis-like mouthpart designed to pierce and drink.
Most distinctive is the filament organ just behind his head: a chitin-ringed aperture that extrudes a glistening, silvery-white line as thin as a spider’s thread but strong enough to haul armored dwarves screaming from a bridge. When taut, the filament hums with tension, vibrating like a plucked instrument.
An old iron collar, warped and half-rusted, is fused into the chitin near his midsection—scars from some failed attempt to make him a living winch.
Backstory:
Tethrix was hatched in a deep crack high on the side of the gorge, competing with his broodmates for the best anchor points. As a youngster, he learned to drop his filament onto anything that moved below—fish in the black river, bats skimming the water, careless goblins crossing rope bridges.
His life changed when duergar engineers attempted to tame him. They trapped him in a crude iron collar and tried to teach him to haul buckets and ore carts instead of prey. For a time, he obeyed, drawn by the constant food and the intriguing vibrations of winches and chains.
But one day, a mine revolt sent carts crashing and ropes snapping. The gorge echoed with chaos. Tethrix’s collar chain snapped, and his instincts roared back to the surface. In the confusion, he fed on workers and rebels alike, drinking until the stone ran slick. When the dust cleared, only the rusted collar remained—a twisted ring he eventually grew around.
Since then, Tethrix has claimed the central span of the gorge as his private hunting ground. He knows the rhythm of patrols, the weight of different boots on the bridge, and the exact moment to strike. To him, ropes and bridges are just bait stretched taut over his table.
