Fear is the first step on the road, and hopelessness is the chain by which He binds. Sorrow is his nourishment. Horror is His form. He preys on those who would submit to bitterness and those who closet themselves in misery, while life moves on around them.
He is terror in the face of decay and disease, and He is inaction in the face of all that is perceived as inevitable.
He is our impotence to resist the ravages of time, and He is our morbidity. He is revulsion and self-deceit, and He is the acceptance of defeat. He breathes His cynicism into our souls and binds us to His will.
He is Grandfather Pest, and He is obstinate, self-indulgent, despair.
Exert from The Book of Pestilence
A Dream of Things to Come
A man, having lost his wife and children by the plague, fled into the forest from his desolate cottage and sought safety there. He wandered about all day long; towards evening he constructed a booth of branches, lit a little fire, and fell asleep, wearied out.
It was already after midnight when a mighty noise awoke him. He rose to his feet, listened, and heard a kind of songs in the distance, and accompanying the songs a sound of tambourines and fifes.
He listened, in no small astonishment, that, when death was raging around, people were rejoicing there so merrily. The noise that he heard kept continually approaching, and the terrified farmer spied a swarming multitude advancing along a wide road. It was a troop of strange-looking spectres that circled round a carriage; the carriage was black and elevated, and in it sat the Pest.
At every step the frightful company kept increasing; for on the road almost everything was transformed into a spectre.
Feebly burned his little fire; a tolerably large firebrand was still smoking a little. Scarcely had the plague-swarm drawn near when the firebrand stood upon feet, extended two arms—the burning part began to glitter with two glaring eyes—it began to sing in concert with the others.
The farmer was stupefied; in speechless terror he seized his axe and was on the point of striking the nearest spectre, but the axe flew out of his hands, transformed itself into a charred corpse with a golden necklace, yellow pus oozing from it’s cracked skin. Singing, it vanished before his eyes.
The plague-swarm proceeded onwards; and the man saw how the trees, the bushes, the owls, the screech-owls, assuming tall shapes, increased the multitude, the terrible harbinger of a frightful death.
He fell down powerless, and when in the morning the warmth of the sun awoke him, the vessels that he had brought with him were smashed and broken, the clothes torn to rags, the provisions spoilt.
He perceived that no one but the plague-swarm had done him all this mischief, and, thanking the Gods that he had at any rate escaped with life, proceeded further to seek shelter and food.
The Herald of Grandfather Pest; As foreseen by Islan Lös
The descriptions of Grandfather Pest are many, some say he is a withered old man supporting himself on a golden cane with burning black eyes. Others swear that he looks like any sweet old man, with rosy cheeks and a white beard. The infamous Islan Lös, a Dream Witch from the eastern lands once painted a grand mural depicting Grandfather Pest inside a Temple of Dream. It was said that any man that studied the breathtaking painting for too long claimed that they saw movement in it. There were also reports of people going mad after gazing at it. It did not take long before the Withchunters tore down the mural and burned Islan Lös on the stake.
Those that remember the painting describe it as surreal and frightening. It showed a vast and fog shrouded hall supported by gargantuan columns. On a huge marble throne sits Grandfather Pest. His face was painted as pale but glowing and his head downcast, as if in deep thoughts. A heavy shadow leaned on his withered body which was depicted as that of an old and nude man with long and pendulous breasts.
Behind his throne, wrapped in coiling white fog stands a legion of shapes. Like silent fingers protruding from the ground. All with heads downcast. Islan Lös claimed that they numbered five thousand five hundred and fifty five in all. This number came to be considered essential to the lore of Grandfather Pest after the passing of Islan Lös.
The first plague to be associated with Grandfather Pest was two centuries ago. It was said that Tancrod; The City of High Walls had been cursed by an unknown deity. Men and women had gone mad, running naked in the streets, laughing while clawing themselves. Within weeks the city was a dead place. No more would its people greet the morning sun with sweet song on the high walls.
Those few that escaped brought tales beyond comprehension by sane men. The people of Tancrod had suffered a great plague, that much was plain. But this was not an ordinary sickness. In those first days, people had dreams, dreams of a man with skin of moss rising from a forest pond. Some were gathering in the city squares, bringing wax candles and chanting trough the entire night. Men did not recognize family or old friends. Many proclaimed the coming of a new god, rising from the deep waters, bringing his blessings to the world. Not long after, people were becoming sick.
The mortality in Tancrod began in autumn. It seemed that almost everyone became stupefied seeing the pain and madness. It is impossible for the human tongue to recount the awful truth. Indeed, one who did not see such horribleness can be called blessed. The sick were maddened by pain. An unholy fire burned in their hearts. They ran trough the streets screaming, killing each other, ripping apart each other, spreading the sickness.
Father abandoned child, wife husband, one brother another; for this illness seemed to strike through breath and sight. And so they died. None could be found to bury the dead for money or friendship. Members of a household brought their dead to a ditch as best they could, without priest, without divine offices. In many places in Tancrod great pits were dug and piled deep with the multitude of dead. And they died by the hundreds, both day and night, and all were thrown in those ditches and covered with earth. And as soon as those ditches were filled, more were dug.
I, Tura, buried my five children with my own hands. And so many died that all believed it was the end of the world.
Years passed and the happenings in Tancrod became known as "The Birth" throughout the kingdoms and empires. The plague struck again, following the same pattern, there were reports of men ravaged by sickness laughing and praising an unknown god. As the years went by this new entity became known by many names, chief amongst those where Grandfather Pest.
...After the pestilence, many buildings, great and small, fell into ruins in every city for lack of inhabitants, likewise many villages and hamlets became desolate, not a house being left in them, all having died who dwelt there; and it was probable that many such villages would never be inhabited. In the winter following the countryside was a haunted place. Villages resembled broken teeth scattered across the land. All was silent...
Many sought to explain who or what Grandfather Pest was. Some believed he had been brought into this world aeons ago, called down to our world from beyond the frozen stars. Awakened in his crystal prison by a one eyed sorcerous people of unknown origin only to slumber deep in our earth. It was not agreed what had finally awakened him from his sleep.
Others believed that Grandfather Pest was the ancient god known as Wixosh, that was no longer worshipped. Wixosh had been a god of the black earth and deep waters. Associated with great serpents, laughter and the underworld. Wixosh had regularly sent spirits of the dead into the living world as his heralds. Festivals in honour of him were held near the end of the year, in winter, when time was coming to the very end of world order and chaos was growing stronger, the borders between worlds of living and dead were fading, and ancestral spirits would return amongst the living.
Young men would dress long coats of sheep's wool and don grotesque masks, roaming around villages in groups and raising a lot of noise. They sang songs saying they travelled a long way, and they are all wet and muddy, an allusion of the wet underworld of Wixosh from which they came as ghosts of dead. It was believed he now blessed men with plague from under the earth so he would once again be acknowledged and worshipped.
Some prophets claim that Islan Lös was the prophet of Grandfather Pest and that killing him has severed our only link to understanding who he is and where he comes from. There are cults devoted to him. Some worship him in the aspect of Wixosh. Some believing that he is a grey god from the stars that spawns his plague only where needed, purging the wicked. Most common people see this as madness and are afraid that it will draw his gaze towards them. Thus cults of Grandfather Pest are hidden, no matter what aspect they worship him in. Savior or destroyer.
When infected by the plague Grandfather Pest brings the victims will feel sick within hours. First it will be like a mild cold, cough and fever soon follows. After a day delirium, hallucination strikes.
Sharp muscular cramps, quickly followed by yellow and black vomit follows. The excreta becomes a black, chunky pulp of blood. After a few days the body is covered with obscene black boils, terrible red rushes and ghastly blue pallor. At this point the infected is raving mad because of the intense and agonizing pain.
For a few minutes of each hour a state of total happiness strikes. The victim of the Grandfather Pest will forget where they are and what state they are in and behave like they are in paradise. The infected will then go insane again. Scratching themselves, try to eat their lips and so on.
At this stage they will stop acting like human beings all together either in pain or bliss. Driven by pure instinct they start to roam around. Screaming, laughing then lying down sobbing, crying.
Plagues and sickness are common, some are mild outbreaks and some are devastating. What separates Grandfather Pest from ordinary illness is the madness both beforehand and during the outbreak. Prophetic mass dreams. Memory loss and sick people in a state of bliss. They will speak of Grandfather Pest with great affection. Calling the plagues his blessing and so on.
There are those that claim that there is no such entity. That plagues are common and that the reason for his "existence" is that man needs to personalize his misfortunes.
Grandfather Pest is also known as; Old Sweet Kiss, Wixosh, The Grey One, Plague God, Filth, Bringer of Filth or simply Pest.
I see Grandfather Pest as a background piece mostly. He can be a mythic figure for added depth in your world. He can be just as real as your other gods, but shunned and his worshippers persecuted. He can also serve as a rumour or tale from lands far away(but getting closer?), If you want to feature a plague in your session or campaign he will perhaps bloom to his full right.