The Forgotten Old Ones

Deities of Death, Madness, and Savagery

Over thousands of years many different people have come up with names and myths and creatures to attribute the source of their deepest fears and the worst evils the world has to offer. What is it within a mortal's heart that causes them to commit acts of horrific savagery? Who was that voice in his head, telling him it must be done? There are gods of cruelty and greed but some gods take this to the next level with a healthy dose of madness. These sources of true evil are known as the Great Old Ones, the Forgotten Gods, many of whom were banished from the realms before time even began because they made the creation of the world impossible- or at the very least very difficult. Most existed before worship, and they do not require it to sustain their existence. They have long been bound and trapped by the benevolent gods (or at least those who prefer existence over nonexistence and require enough order for their own machinations).
That said, they are very old, very powerful, and can still reach out into our world with their corruptive influences. There are many of these gods going by many names, but three stick out over all others and date all the way back to the earliest known texts. Some myths are just myths to explain why there is evil in the world, but the deities of Oblivion, Madness, and Savagery actually affect the world. They reach out at times through history and twist the minds of mortals, leading them to commit horrible acts or seek out ways to bring the Old Gods back into the world they were cast from. These gods have held many titles but no one influenced by them have ever been willing to attribute them an actual name and it is likely they have none. The Old Gods are sometimes also called The Hungry Gods because one thing they all seem to have in common is that their worshipers believe them to require "feeding'- generally ritualistic sacrifices of some kind. Very few gods other than these oldies actually require worship this dark in nature. Most cults to them work tirelessly to unleash them from their prisons.

The Dark Heart

Alias: The Spiraling Dark, The Endbringer, The Coming Dark, The Calling Void, The Endling God, The Emptiness, The Negative Plane
Domains: Death
Portfolio: Oblivion, Fear, Emptiness, Extinction, Suicide
Alignment: CE
Symbols: A black circle with Spiral, Oleander

Origin Story: The Dark Heart is most commonly referred to as The Spiraling Dark, one of the eldest gods of the Draconic Pantheon. In the beginning, according to the dragons, there were only the stars and the void, and try as the void might, they could never swallow the stars of creation. The stars created the other gods so that they might trap and contain this Calling Void that sought absolute destruction and nothingness. The world could not be made until this being could no longer oppose them. It was contained within its own dimension and hidden within the void of space, according to some stories. But it was powerful and influential and it still managed to send its dark tendrils into the world of mortals. The first worshiper of The Spiraling Dark was the father of the chromatic dragons, Nammu. Though he was the first real champion of this dark entity and its intent to unmake all of creation, Nammu slowly evolved, seeking destruction only of the civilized world and the notion of order. The Spiraling Dark is credited by dragons as being the great manipulator who caused the wars that resulted in the shattering of the First World.
Compared to most of the Old and Forgotten Ones, The Dark Heart is still known somewhat in myth and popular culture. Few think of them as an actual real deity and they are more often considered a scary bedtime story or made up apocalypse myth. In most of these myths the day will come when the Endbringer breaks free from it's container and devours the gods who imprisoned them, followed by all the planes and worlds now left unprotected. We would know it was coming when the stars wink out, the last being the sun, and then there would only be dark and then the same nothingness from which everything originally sprang. After the great devouring, the Dark Heart would then consume itself and that would truly be the end of all things. The container this creature lives in is not supposed to be accessible by the living - not even the gods- because it would simply unmake them. Some think that the Negative Plane itself, an antilife plane that touches the borders of the shadowfell, actually IS this entity in the flesh. 
Worship: Worshipers of this entity are exceedingly rare, but they do exist. The vast majority of individuals that this creature reaches out to have simply gone mad with fear, so tiny and powerless in the face of a being of such unparalleled age, malice and hunger. Those with any mental faculties left long only for one thing- the end- and most commit suicide eventually. Even other gods of pain and murder and disaster have a healthy fear of this god, darker and colder than all of them combined. This is a being that does not wish for simple violence or death- it wants the end of existence itself. Most worshipers are small doomsday cults that believe that existence was a mistake and life is a cruel cyclic sentence that no one deserves. Few have actual contact or boons of this god and most are just bitter individuals who have lead extremely tragic or unhappy lives. Leaders of these cults that have made contact with the Dark Heart are told how they might work towards freeing it from it's plane. Many perform rituals that apparently send sacrifices, willing or not, to that plane to strengthen its power. Others kill ritually for the same purpose or even partake in mass suicides. Worshipers believe that once it becomes powerful enough it will be able to break through the barriers of its prison and free itself. Others believe it is up to them to break that barrier somehow. 

The Beast

Alias: Lord of the First Forest, The Raving Hunger, The Savage King, The Gnoll-father, The Elder, The Dreaming One, The Beast Below
Domains: Death
Portfolio: Insatiable Hunger, Mindless Savagery, Carnal Temptations, Gluttony
Alignment: CE
Symbols: A Black Fang, A Crown of Bone, A Skull with Antlers
Origin: The Beast is, indeed, a very Old God. It was not prisoned by the benevolent gods until after mortals crawled the planet's surface and some of them have never forgotten this savage terror that stalked the First Forests- particularly the druids of the ancient elves, the gnolls, and the unseelie fey. This was a being of unnatural ferocity, unlimited cruelty, and insatiable appetite. Unlike most other gods, It roamed the ancient world of the living in physical form, the great beast of the deepest woods, slaughtering and reveling in bloodshed, a crown of bone and viscera upon its ghastly head. It did not simply kill to eat - it delighted in playing with its food, tormenting it, skinning it, pulling it apart piece by peace, feeding as much on the creatures pain and fear as it did it's flesh and organs. This creature of the hunt brought imbalance to nature and made the primeval world exceedingly dangerous to traverse without being devoured. It also brought all manner of pestilence and parasites into being, the tiniest creatures of ceaseless hunger. It is said by some to have created the first "Gulthias Tree" which spawned the first plant blights. The Beast was the creator of most monstrosities that exist, the source of their evil tendencies being the blood of this Beast, as they were forged from its own torn flesh. This god so reveled in pain it even inflicted it upon itself. It used its own flesh and blood, as well as the discarded parts of many other slaughtered beasts, to form ghastly creatures. Though all monstrosities might call The Beast their father, only one legendary monster can claim this entity as proper kin - the legendary Tarrasque, called by some the Progeny of the Beast. Some claim it was the only monster that was birthed instead of molded and most clearly reflects the true shape and form of the Beast. It was also eventually bound by the machinations of the gods.
Though he existed for a time on the ancient world, this chaotic god lived and worked in direct opposition to the main deity of life and balance and orderly cycles, and for its many transgressions against natural order, the Beast was dealt with. Too dangerous to fight directly, it was instead lured into a trap by the deity of nature and a spell was placed by the god of all magic- an unending slumber. It was then tucked away somewhere beneath the earth, so far down that nothing could find and awaken it.
Worship: Though the Beast now sleeps away the ages, it is a being of such primordial power that even it's dreams can influence the world. Its dreams are dark, full of furious hunts and violent carnal instinct and at times these dreams touch the minds of beasts and mortals, sending them into the same mad frenzy it is experiencing. These dreaming individuals go on mad killing sprees, kill their pets or family members, harm themselves in violent fashion just to dance in the blood, and often feast on raw meat. Some of them even try to eat themselves. Most think they are truly dreaming and awaken with horror to discover what they have done. Some who dream with the Beast never shake the need for the dark ecstacy they experienced and lose their minds or seek out further connections with the Beast, wanting nothing more than to join in his wild hunt once again. Gnoll-kind and other monstrosities have a deep blood connection and are most often influenced but so are many creatures that exist closer to nature and baser instincts, including the Lizardfolk and some even think the Yuan-te worship this beast in the guise of a snake. The Beast is also known to lucid dream- to actually acknowledge the dreamers and communicate its will. This being knows it sleeps, that its wonderous dreams are not reality, and it seeks to correct this indignity and especially to devour the gods of nature and magic who betrayed and trapped it.
The Beasts followers, those who manage to find each other and form small cults, seek to "feed" it, ritualistically until it can be found and released. By feeding it and strengthening their connection they hope to dream with it again and again until the real thing happens. Only the greatest of the Beasts fellow hunters will be spared and seen as a part of it's hunting pack. These "feasts" can be ritualistic man hunts or especially violent sacrifices, and cannibalism is especially popular. These banquets nourish the beast through its unjust imprisonment until its location can be discovered and the enchantment dispelled. When the slumbering elder finally wakes, the Final Hunt can begin- a real hunt they will join their master in- a wild hunt that never ceases and leaves the world in rightful terror in the face of their hunger, vengeance and blood-soaked revelry.

The Mad God

Alias: The Cacophony, The Howling Chaos, The Ten Thousand Voices, King Aboleth, The Stranger, The Eldritch Heart, The Waiting Corruption, The Star Skulker
Domains: Death
Portfolio: Delusions, Extreme Fear, Dread, Paranoia, Psionics, Corruption, ??????
Alignment: CE
Symbols: Five Eyes in a Circle
The Mad God goes by a huge plethora of names because very few have actually been able to amass a comprehensive history or identity for it across cultures and regions. Many Old Gods of insanity might be one in this same being. Many think it should be named "The Cacophony" because what is common among all worshipers is hearing a screaming cacophony of voices and noise that can drive one to a psychotic break or even cause death. It is a being of pure madness and fear and it is said to reach out from the Far Realm beyond the stars and make contact with certain mortals. It's goal is to find a way to reach this realm from the place it is trapped. 
Origin: According to some very ancient draconic scripts which speak of this creature (which they call "The Mad Thing From the Edges") it is kept from entering this world by a divine shield placed by the gods. This is what separates our planes of existence from the Far Realm and the only thing protecting the world from being corrupted and twisted into something horrific and alien. According to these texts the being is akin to a divine cancer that grew from the wreckage of the countless battles between the Spiraling Dark and the Infinite Stars. This mad, screaming entity of pure conflict and pain and madness is half alive and half dead, torn between the want of creation and the need for destruction. It almost devoured the first world and even might be what corrupted The Beast into what it became. 
Worship? The Mad God is said to be the creator of all aberrant creatures, including the primordial aboleths and the Ilithids which were found much later incubating below the earth. The aberrations borne of this ancient contact before it was pushed back into the far away places are the most common worshipers of this being as they are the ones most aware of its presence. Another near-universal experience among those who have had contact with this creature and survived in-tact is the development of psionic abilities. aberrations

Temples of the Old Gods

There are very few actual standing temples to these ancient entities. Some temples to the Mad King are supposedly to be found within the Underdark, wherein lives several societies who have been contacted and influenced by him. Temples to the Beast are supposedly found in the most remote wildernesses in the world such as the Ixil Rainforest, though they are generally ruins are so old and crumbled they are scarcely even noticeable or recognizable. Temples to the Dark Heart are probably the most obscure. This being was cast away long before any mortals roamed the world so most temples that exist are small altars hidden and scattered across the world, often attended to by a lone priest or worshiper who built it. Fully built temples may not even exist.

Worshipers

Worshipers of the Old Gods are almost always those who have been directly contacted by this being in some way. These worshipers often go mad, become hermits or sages to try to understand what they've been shown, or dedicate themselves as acolytes to strengthen their connections with these beings. In the case of stronger connections sometimes people make pacts and become warlocks dedicated to them. The truly chosen of them become death clerics or develop into sorcerers whose powers stem from their connection. There are small cults to these gods but they are rare and not all of them actually know who or what they are worshiping. 
Worshipers of The Mad King or those he has touched or influenced often have strange psionic abilities; these includes many  Duergar, Ilithids, and the Gith.

On-Brand Worshipers

• Barbarian: Berserker or Zealot
• Cleric: Death Domain
• Fighter: Psi Warrior
• Monk: Way of the Long Death
• Paladin: Oathbreaker
• Rogue: Soul Knife
• Sorcerer: Aberrant Mind
• Warlock: Great Old One
• Hermit Background
• Acolyte Background