HopFish (Crawling Piranha)
Well, these guys are pretty simple. Piranha are already terrifying. Some cave fish have already learnt how to climb up rocks. Piranha like to jump occasionally. What could make more sense than a Piranha species in dangerous circumstances evolving stiffened fins and hopping out of the river after their prey?
Albino of course. Maddened by blood. Strange little “click click click” as the first few leave the water. Then you turn and shine your lantern at the ground and see it covered with these white, twitching, hopping fish. Tapping forward awkwardly on their fintips. Their jaws churning.
They wouldn't be able to stop prey running, or follow them for very long. So they would probably attack where movement is constricted. A series of slight, low islands in a river. Or leaping out of a waterfall as you cross it. Climbing down after you as you attempt an emergency rappel.
They are a pretty low level threat if you think about it, but everything else I've done is terrifying so why not?
Some called them Debtsmen, but this name has been forgotten now.
Agonised puritan secret-thieves. Slave-hunters. Desperate fighting philosopher-cowards. The ultimate Sophists, a life built on lies and hidden knives.
They guard the Hive of Glass and the legendary Alepholith* at its centre. They sometimes shepherd the Stormsheep. They map and re-map the Underdark. Searching.
The skin of a Knotsman has bumps. Throbbing nodules of mixed up red and blue. Sticking up through the skin, almost breaching the pale flesh. Its their blood.
Think of two hose-pipes braided together in irregular lumps like the cables behind a cabinet. Then imagine them filling up with water, turgidly locking into place as the stuff flows through. These are the veins and arteries of the Knotsmen. They are mixed up and tangled in the flesh. The pressure forces lumps of body-tubing up under the skin where it ticks with the pulse like a forehead-vein. Every Gordionites tongue has a golf-ball sized lump in its centre where the veins mash. If they were to accidentally bite down on this, they would bleed out in minutes.
The Knotsmen are in incredible discomfort. It hurts to do anything. They will deny this. They are not in pain. You can see in many, broken pins sticking from the veinal twists. This is where some have desperately and dangerously tried to unknot their own flesh. The pins break and cannot be removed. They will deny this. Press again and they attack. Suicidal rage before the truth.
Knotsmen want armour but it makes them very uncomfortable. They fight so very very carefully.
The Knotsmen sold their children’s souls before their birth. They live in debt. The debt can be redeemed by surrendering another soul that's not been made. They hope. So every one that lives goes on, knowing they must feed fate their children to escape.
They will not admit this is true. They will not accept this is wrong. They will hold fanatically to the death-deal they have made and, every time each one denies the truth, another knot forms within them. There is a strange power in this.
Old Knotsmen are rabid, twitchy and pustulent with distended knot-flesh. Their leaders and priests have curling back-turned bones and are not seen.
The Knotsmen often run. Young and sometimes old. Often with their children. They try to escape. But this is the Underdark and there is nowhere to escape to.
They obsess over maps. They are seeking their escaped children. Hunting them to ensure their own survival. Not just the parents but the whole culture. Any breaking of the bond of soul-debt is seen as the most terrible threat to all. An obscene and unforgivable crime. Evil and inexplicable. The map-need helps them find their hidden kids. It is a dual-edged blade. Knotsmen know the Underdark better than anyone. Their escapees are well informed.
Knotsmen hoard and trade map-knowledge and will hunt the slaves of other cultures for fun and profit.
It lies in the centre of a labyrinth of volcanic glass. Anyone entering can see every single thing inside. The glass cradles light like cathedrals carry sound. Distorted fun-house views of lighted rooms are glowing in the quartzy walls, accessible to all. Nothing is what it seems. Few have survived. Many have tried. The Alepholith is within and anyone who seeks a secret thing can discover it there.