Yogg-Saron by lawgiva

One of the greatly malevolent and ancient entities known only as Old Gods, Yogg-Saron held chaotic tyranny over the world of Azeroth in the very distant past, and was responsible for the creation of the Curse of Flesh to "facilitate assimilation" of the Titans' creations. When the Titans waged war against the Old Gods and shattered their citadels, they found that the infestation of the entities had grown so severe that destroying the Old Gods would also lead to the annihilation of Azeroth. Instead, the Pantheon took measures to neutralize the Old Gods' power and bind them within Azeroth for the remainder of its existence. Yogg-Saron was sealed away within the depths of Ulduar in the far northern reaches of the infant world, and had six watchers assigned to it which served as wardens for its near-eternal imprisonment; the Titanic watchers known as Loken, Thorim, Hodir, Tyr, Mimiron and Freya.