Hastur

Hastur, the King in Yellow, is a Great Old One and one of the most powerful forces in the universe. Hastur himself is one of the most well-known Great Old Ones across multiple dimensions, although no dimension is known to call it his home.

Appearance
Like many Great Old One's, Hastur's form is not finite, and he can appear as any number of beasts and creatures he desires. That said, the most common of forms he is seen in is what has come to be known as "The King in Yellow".

Modeled from a play of the same name (of which Hastur is the star character), Hastur is often seen wearing bright yellow robes with just a bit of wear to the color. The clothes typically extend down to his feet, and his face is rarely seen beneath the hood as little more than an empty nothingness. From below his cloak, dozens of tentacles burst forth. Despite his humanoid appearance, it is assumed that nothing human is under the clothes.

Hastur's actual face has never been witnessed by an individual who has survived seeing it. Supposedly, his face is so horrendous and monstrous, that merely viewing it would drive one entirely insane. On occasion, a face can be seen without being driven insane, however individuals who have prodded further have found it to be no more than a mask, which also alters its appearance regularly.

One common element of Hastur's appearance is known as the "Yellow Sign". It is similar to a question mark, with two ends curling off the bottom towards each other. It is always seen with Hastur in some design, although it is not always yellow in its actual appearance. Viewing the symbol for more than a few seconds would cause anyone viewing it to see it as yellow.

Description
Like most Great Old Ones, where Hastur came from is unknown. Common theories assume he is actually the result of a human gaining a blessing from Cthulhu himself, however stronger academic circles have supposedly found a connection between him and Yog-Sothoth, placing Yog-Sothoth as his father, Cthulhu as his half-brother, and possibly Ithaqua as his offspring. Documentation on Hastur is sparse, as he is very difficult to approach without being driven insane.

Hastur is known to regularly attend a play at the Yellow Theater, a building built by his acolytes and followers. These people wear nothing but yellow (although many of them may wear dressy clothes such as expensive business outfits and decadent dresses), and all of them have dyed their hair a gold color to coincide with the religion. The theater itself is almost entirely yellow, with the only source of color being the curtains, which are still a traditional red.

"The King in Yellow", a Play in Two Parts
The play itself is a nonsensical story that makes little sense to outside viewers. It appears to tell the story of a royal man who created the symbol, and who claims ownership of the Yellow Throne. From here, details become confusing, as The King in Yellow goes from dimension to dimension to expose his ownership of the throne to varying degrees of success, showing his lineage, and explaining to the audience his importance.

Beyond this narrative, the story doesn't follow a cohesive plot. Characters will appear to say incoherent lines such as "I don't actually have the time, I'm so very sorry", and leave with little else to say. Background characters will wander through the scene without any obvious direction, and there is a scene in which two major characters speak while another character forcibly walks between them, shoving them apart, and walks away. Multiple viewings of the play shows some of these details get omitted in certain versions or are outright changed.

By the end of the play, those who viewed it will remark it as a masterpiece, and will immediately bow to Hastur's genius if he is present. They will strip themselves of all clothing that isn't yellow (even if it renders them nude), and the cult that held the play will give them a single yellow cloak. From here, these individuals often return home, scratching the symbol of the Yellow Sign into their belongings, painting objects yellow, and purchasing only yellow clothing. Members of the cult will actively walk through the streets nude if unable to wear yellow, and have on more than one occasion have been seen painting their bodies yellow regardless of the toxicity of paint. Individuals who call them out on this behavior as met with dismissal, and are often mocked for not being in the good graces of "The King in Yellow".

Individuals attempting to flee the theater (as viewings are usually non-consensual) will often be brutally killed by Hastur. Nonbelievers and people who attempted to flee the theater will be forced back to their seats by the cultists or tentacles from Hastur himself. Once forced back to their seat, Hastur will move from his balcony to the stage. Cultists in the room will not move or speak while Hastur moves except to restrain fleeing viewers, and Hastur, once on stage, will grapple whoever attempted to flee (even multiple people at once) and drag them towards the stage, showing the Yellow Sign to these people for an extended period of up to twenty minutes. After this, these people will ritualistically disembowel themselves on stage regardless of their age or prior behavior. Each one will be presented with a weapon of some kind by the cult, and will slice their bodies open by carving the Yellow Sign in various areas on their body. Once the carving is done, the victims will stay where they are and wait to die of blood loss, carving further symbols if it isn't occurring fast enough. Once this ritual is over, the play will proceed, with actors stepping on and over the bodies of the deceased.

The viewers of the play will be apprehensive and frightened, however the further the play goes (even if they avert their gaze, cover their ears, and lower their heads), they will become more interested. No person has ever ignored the play after the halfway point. No person has ever refused to join the cult after the conclusion of the play.

Other Details
Beyond the play itself, Hastur has never been seen talking, although supposedly higher acolytes and zealots can enter his realm to speak with him on his chair. Supposedly the Yellow Throne sits in a dimension known as Carcosa, of which he is the highest authority. Nothing else is known of this dimension as non-zealots and spies have never returned alive or sane.

Insanity
Like most Great Old Ones, learning too much of Hastur will lead to the death of an individual or pure insanity. Supposedly viewing Hastur's face would drive any being, man or god, to total insanity, unable to handle the images they see.

Individuals driven insane by Hastur will typically remark that they have failed him. Regardless of their feelings towards authority or their past behaviors, these people will become consumed by fear and regret at upsetting Hastur, begging him to release them from their pain.

There is no cure to insanity created by a Great Old One, and no way to reverse the power. Even gods themselves induced with this madness cannot remove it from themselves.

The Yellow Sign
The Yellow Sign is one of Hastur's signature objects. What it does is very poorly understood, but details have been gleaned from its use.

Firstly, the Yellow Sign does not have the same power when used by others. Those who hold medallions of it or carve it into objects will note that it lacks the same power. While it is possible to gain an unforeseen headache by staring at a false Yellow Sign long enough, only Hastur's Yellow Sign is particularly dangerous.

When viewed by a person for any period, it induces a trance that cannot be broken unless the Yellow Sign is removed from the gaze of the person. At least two known attempts have been made to destroy the Yellow Sign by outsiders, one of which was successful, however it simply rematerialized in Hastur's hands in milliseconds.

After viewing the Yellow Sign, victims will become either suicidal and begin killing themselves in methods that cause death by blood loss (albeit at a slow pace due to use of fine yet deep cuts on the body), or victims will become wholly obedient and offer their very bodies and souls to Hastur either in forgiveness or thankfulness.

The Yellow Sign can be easily directed by Hastur. If he doesn't want it to do anything, it won't. The Yellow Sign can be stolen, however thieves who take the Yellow Sign will find their appendages that touched it will undergo rapid degeneration and be inflicted with jaundice. The thief will not survive more than 48 hours before death, even if death would be entirely impossible (such as the death of Death itself). Even if returned, these victims will find themselves haunted by hallucinations of Hastur in their own dwellings, and may even see his appearance in place of their reflections. At least five deaths have been caused this way, with Hastur utilizing the power of a reflection to force a thief to beat their head against a wall until they began bleeding, and held them from leaving until they died of blood loss. It is assumed Hastur does not try to hold onto the symbol particularly hard to allow this situation, especially considering he can rematerializes it in his hands.

Power through Terror
Hastur gains strength from the terrors of society. Regardless of whether his opponent is scared or not, all that matters is that fear exists in the universe. Often his cults will go to local areas near a fight with Hastur to cause riots, murders, and other deplorable acts to incite a widespread panic. As these cultists do not have any self-preservation in mind and will die for their leader, authorities are forced to shoot any cultists, and victims will find that cultists will continue their horrible acts until the battle is over. One such cultist, killed by a neighbor, found that his neighbor, still alive, had been repeatedly raised off of and lowered onto a metal plate holding a temperature of 400 degrees to incite serious burns and pain while his family and nearby captured neighbors were forced to watch, many of whom were also tortured. Another cultist in the same riot began tying up individuals at a supermarket with the help of an inhuman beast, and began systematically pouring toxic liquids into their mouths, waiting for the death of the current victim before moving on.

Fights with Hastur have terrible overarching consequences, and even the most powerful of godly societies are besieged by seemingly endless cultists with monstrosities defying natural law.

As Hastur gains his powers from terror, especially the closer one gets to him, he becomes incredibly dangerous. Combatants will find Hastur becoming so powerful, that he is basically immune to damage altogether. Additionally, Hastur seems to shrug off most physical blows, and combatants who are primarily focused on combat with weapons like guns, swords, bare hands/feet, and any other sort of weapon including energy-based blasts will find them barely effective. Hastur is known to be vulnerable to magic, however the magic that hurts Hastur must be cast from sanity, and even then it is possible for the sanity loss to cause panic in the user, further powering Hastur in combat.

Tentacles
Hastur has a seemingly endless sea of tentacles underneath his cloak. These tentacles are used for a variety of reasons. As they can stretch as long as needed, can change size depending on the task, and have enough strength that a single tentacle, if used properly, could simply crack a planet in half through crushing.

In combat, Hastur uses these unbelievably powerful pieces to crush his victims or deliver blows with unbridled force. While it is not impossible to sever a tentacle, it does not particularly harm Hastur in any way, and the broken tentacle will break off, replaced by a new one.

Immortality
Hastur himself is ultimately incapable of dying. If defeated in combat, he retreats to slumber, and while sleeping, he is immune to any forms of damage. This does, however, cause him to recede back to his home dimension, believed to be Carcosa.