Yog-Sothoth

"Yog-Sothoth knows the gate. Yog-Sothoth is the gate. Yog-Sothoth is the key and guardian of the gate. Past, present, future, all are one in Yog-Sothoth. He knows where the Old Ones broke through of old, and where They shall break through again. He knows where They have trod earth's fields, and where They still tread them, and why no one can behold Them as They tread."

- H.P. Lovecraft

"Imagination called up the shocking form of fabulous Yog-Sothoth – only a congeries of iridescent globes, yet stupendous in its malign suggestiveness."

- H.P. Lovecraft "It was an All-in-One and One-in-All of limitless being and self – not merely a thing of one Space-Time continuum, but allied to the ultimate animating essence of existence’s whole unbounded sweep – the last, utter sweep which has no confines and which outreaches fancy and mathematics alike. It was perhaps that which certain secret cults of earth have whispered of as YOG-SOTHOTH, and which has been a deity under other names; that which the crustaceans of Yuggoth worship as the Beyond-One, and which the vaporous brains of the spiral nebulae know by an untranslatable Sign..."

- H.P. Lovecraft and E. Hoffman Price "IT seemed to say, MY manifestations on your planet's extension, the Ancient Ones, have sent you as one who would lately have returned to small lands of dream which he had lost, yet who with greater freedom has risen to greater and nobler desires and curiosities. You wished to sail up golden Oukranos, to search out forgotten ivory cities in orchid-heavy Kled, and to reign on the opal throne of Ilek-Vad, whose fabulous towers and numberless domes rise mighty toward a single red star in a firmament alien to your earth and to all matter. Now, with the passing of two Gates, you wish loftier things. You would not flee like a child from a scene disliked to a dream beloved, but would plunge like a man into that last and inmost of secrets which lies behind all scenes and dreams. What you wish, I have found good; and I am ready to grant that which I have granted eleven times only to beings of your planet - five times only to those you call men, or those resembling them. I am ready to shew you the Ultimate Mystery, to look on which is to blast a feeble spirit. Yet before you gaze full at that last and first of secrets you may still wield a free choice, and return if you will through the two Gates with the Veil still unrent before your eyes."

- Yog-Sothoth addressing Randolph Carter

Yog-Sothoth is a vastly powerful cosmic entity from the works of H.P. Lovecraft, and is one of the Outer Gods, yet he is the strongest of them - dwarfing even the famous Cthulhu in the same scale that Cthulhu dwarfs humanity, and a truly cosmic menace that is beyond mortal comprehension. Yog-Sothoth is the embodiment of time and space across an essentially infinite number of space-time continuums, for all intents and purpose, he is connected to the multiverse.

History
According to the mythology of Lovecraft, Yog-Sothoth is a limitless cosmic horror that is connected with all of space and time yet is locked away from mainstream reality - the monstrous deity sees all and knows all and can impart knowledge to anyone foolish enough to seek its favor, which often required human sacrifice or worse and would ultimately bring calamity and ruin to the would-be-follower.

Like many Lovecraftian deities Yog-Sothoth has a number of avatars and even followers (such as the Chorazos Cult) by which to expand its influence and although classed as "evil" is technically an amoral character that is simply beyond our understanding of petty morality or sanity (indeed Lovecraft wrote in a very dark fashion that swayed away from moral absolutes and saw the universe as being cold and cruel by its very nature).

Description
Like many Lovecraftian gods, Yog-Sothoth has many different appearances throughout the various stories of the mythos, by various authors. However, there seems to common agreement that Yog-Sothoth visually manifests as a mass of glowing orbs, with eyes or tendrils in some versions, and in others simply the orbs.

It is heavily implied, if not outright stated, that Yog-Sothoth is omniscient, and is locked outside the universe, meaning he knows and can see all of space-time all at once, that there is no secret hidden from Yog-Sothoth.

Appearances
Yog-Sothoth's name was first mentioned in Lovecraft's novella 'The Case of Charles Dexter Ward' (written 1927, first published 1941). He goes on to be the driving force of the short story The Dunwich Horror, in which he fathers twin children with a human. It is later mentioned in At the Mountains of Madness as being the thing beyond the mountains that even the Elder Things fear.

Trivia

 * It is a common misconception that Yog-Sothoth is more powerful than Azathoth. This is not true, however, as Yog-Sothoth is a part of Azathoth's dream reality (As evidenced by XXII. Azathoth)