Tharizdun

Tharizdun, the Chained Oblivion is the mad deity of death and trickery. It dreams the infinite Abyss and its demon hordes into being, and dreams aberrations into being beneath Exandria.

Appearance
Tharizdun is depicted, if at all, as "a creature of rolling, hungry ink and darkness", a spreading cloud of lightless destruction. It is endless, black, inky, filled with teeth and malice, laughter and hatred. While the other entities in the Pantheon have different interpretations of how they are depicted in artwork, tapestries, and tomes, every record of Tharizdun is amorphous and without physical manifestation.

Personality
Tharizdun is not best understood as a god like the others. Its "mind" is profoundly alien, and does not carefully form complicated plots. It is a primal, subconscious force of annihilation that insidiously corrupts what it can to undermine everything, opportunistically masquerading in the forms of what other minds desire, and seeping in to twist those minds' intent and perspective toward Tharizdun's own destructive ends.

History
Tharizdun is an ancient entity, possibly older than even the other gods. During the age of the Founding, the Primordials' slaughter of the mortal races the creator gods had formed drew the attention of the demons of the Abyss, who poured into the world to feast on the carrion. In the battles that followed, the Prime Deities locked Tharizdun away securely, or so they thought.

During the Age of Arcanum, a priest of Tharizdun, Acek Orattim, made his base in Gatshadow Mountain, under which the Chained Oblivion had been imprisoned since the Founding. The priest channeled Tharizdun's power, causing Gatshadow to grow notably in height compared to the other Cliffkeep Mountains and grow a maze of tunnels within. From Gatshadow, Orattim spread his evil corruption across the region.

Before the Calamity, the Betrayer Gods each forged a sentient weapon with the life force of a greater fiend: the Arms of the Betrayers. Tharizdun forged a reality-warping stone dagger called the Blade of Broken Mirrors using the life force of a glabrezu.

Tharizdun was released once more onto the Material Plane during the Calamity, causing untold destruction and chaos.

One of the climactic fights of the war came about when the Prime Deities sought to banish Tharizdun. Moradin used the Core Anvil to craft the Prime Trammels used in the Rites of Prime Banishment. Ioun baited Tharizdun to her central temple, resulting in her near-destruction and causing her temple to sink beneath the earth in her sorrow. With the blessing of Avandra, four Prime Trammels were attached to Tharizdun, and Pelor prevailed in a spectacularly violent battle with the mad god. Badly defeated and wounded, Tharizdun retreated to Acek Orattim's realm, but Pelor chased and banished Tharizdun there, beneath Gatshadow. Acek was rumored to be so suffused with his master's power that the divine banishment tore the priest's body apart.

It is said that six sets of divine shackles hold the Chained Oblivion at the bottom of Abyss, their power anchored somewhere in Exandria. The locations of each shackle fane are closely guarded secrets within the highest clergy of the Dawnfather and the Knowing Mistress, although one is located in the crypt deep beneath the Chantry of the Dawn in Rexxentrum. It is feared that the nature of Tharizdun, being unlike the other divinities, could shatter the Divine Gate alone if unleashed. No one knows how few shackles must remain to keep it at bay.

When Lolth was banished early in the Calamity, her drow fled the surface world to rebuild underground. In Tal'Dorei, Tharizdun took advantage of Lolth's reduced influence: it began to whisper to the drow nobility, and its aberrations subtly besieged the drow civilization in the darkness. By 812 PD, the drow of Ruhn-Shak were on the edge of utter dissolution, tearing themselves apart with paranoia-driven violence and trying ever more desperately to clamp down on the chaos.

Meanwhile, the re-formation of Cognouza into a broken collection of many minds had caught Tharizdun's attention, and the mad god helped Cognouza along and influenced the form it took. Similarly, Tharizdun, sensing opportunity in what Obann wanted, allowed Obann to imagine into being a manifestation of Tharizdun's influence in the form of the "Angel of Irons". In both cases, the influence was supposed to subtly lead toward Tharizdun's broad goals.

Kingsley Tealeaf's dreams of his confinement and escape from Lucien included memories of strange black chains that invisibly wove through Cognouza, now broken, the sound of them shattering between worlds, and the angry, unknowable, primal, ancient cry that he could never forget. This represented the loss of Tharizdun's investment in the city.

Worship
Those who are foolhardy enough to follow such twisting destruction as the Chained Oblivion are often spurned, hateful, and chaotic souls who fall through the cracks of society. A bit of inherent madness left unchecked opens the door to the creeping Void that draws those who worship this entity. The characteristics of the Chained Oblivion’s influence are bouts of uncontrollable hunger, uncharacteristic aggression, and eventually violent mania. The higher acolytes of Tharizdun, as part of their ritual of ascension and to show their true faith, often remove their eyes so they can peer through shadow and light with its boon.

The Chained Oblivion and its followers often deceive other sects into aiding their efforts by creating a false idol entirely. Its intent, as best can be ascertained, is to consume and destroy.

Known worshipers

 * Acek Orattim – Priest of Tharizdun during the Age of Arcanum and the Calamity.
 * Jayne Merriweather
 * Angel of Irons cult
 * Obann – Obann was not aware of the true identity of the Angel of Irons until he failed to break the Fane, after which he was destroyed and what remained of him twisted into Obann the Punished.
 * Vence Nuthaleus – It is unknown how much Vence knows about the true nature of the cult of the Angel of Irons. He collaborated with fellow cultists Respa and Adeen in an attempt to break one of the fanes holding Tharizdun in the bottom of the Abyss.
 * Cardinal Respa - Cardinal in the Chantry of the Dawn. Cardinal Respa led several cultists in a prayer of worship for the Angel of Irons and hoping for its release.
 * Adeen Tasithar (presumably via domination) - he confessed to aiding the cult, but seems to be unaware of why and how he did it and genuinely horrified by his actions, even when talking to who he thought was Vence. The Mighty Nein therefore suspect that he might have been under the control of Obann.

Trivia

 * The epic-level adventure hook Scion of Oblivion in the original Critical Role: Tal'Dorei Campaign Setting involves a piece of Tharizdun's power that was cast into the Shearing Channel in its epic battle with Pelor during the Calamity. That gradually growing power has mutated a kraken into an abomination that horrifically transforms everything around it—creatures, ships, the weather—as it rises and seems to build an army for some larger attack.