Two hundred and fifty million years ago a war began when something tried to kill the earth. No-one alive knows what or why. The coal burned in the ground and poisoned the sky. The forests were consumed en-mass. They died to fast to leave a trace of oil. A fungal spike occurred. Vast growths feeding on the rotting flesh of disaster-taxons. Whole species. Most species. Big enough to leave a negative trace in rocks we find today. A speckling of empty oil beds, fossil fungal spores, shocked quartz and fullerines holding some unknown extraterrestrial gas.
Ninety four percent of everything alive was killed. We descend from the surviving six per cent. The war was lost by life, which shrivelled on the earth.
But not quite.
One survived. Carrying the memory of the war beyond Gowandaland. The Trilobite. A blind and sleepless knight in clanking armour clad. Wandering the hidden places of the world, carrying its burden through the empty night, lest darkness rise again.
They saw the first light on earth. Not the first made, but the first seen. The first eyes possessed by living things. The first to fully know the light, the first to fear the dark. The first to know what shadows were, how colours work. The first to see the other suns beyond the moon. The first to see the light that stains the sky before the dawn. They loved the Earth.
Trilobite eyes are subtle hexagonal hives of liquid-bright calcite. They see in depth, with great complexity. Their sight became a curse. The artful sheet-glass transparency made them prime, unavoidable, and sole witnesses to the holocaust of earthly things. A scale and intensity of murder forgotten by prophets, a soul-blinding horror.
The few that lived abandoned sight, they moved into the silent knots within the planets skin. They waited while the rotting flesh of every living race piled past in torrents of corruption. They waited while the fungal lords ruled briefly on the dying corpse of earth. They waited while the slow rebirth of life began again. They concentrated on survival. They have a reason to go on. Apart from the strange myconid dream-mind that might or might not span the globe, they are the only ones who remember. The only living thing to even know the threat exists. They are hiding but they are not beaten, they know it will return.
A Trilobite-Knight is a six-foot, silent, intelligent bug. Clothed in natural plate and following something pretty much like the chivalric code. Fight with honour on life's right hand. Never kill a surrendered foe. Defend the weak against the strong. Uphold the right.
They will challenge adventurers to learn their worth. It is not so unusual to find a Psychopyge sword-bearing bug, rearing in heraldic defiance across a needle-thin abyssal pass. Or duelling on the rocks through Nightmare Falls. Sometimes appearing unannounced when danger lurks. Striking evil from the darkness.
They will not help Myconid slaves, or interact with myconids in any way. No-one knows why.