Shudde M'ell is a mile long great grey worm-like creature that burrows through the earth, melting all rocks in its wake. It is said to be the supreme regent of the Chthonians as well as the largest and most powerful of the race.
Shudde M'ell appears as a colossal worm with tentacles sprouting from its head, and is so large that it can cause earthquakes by simply moving. Although Shudde M'ell is thought to have lain dormant beneath Ethiopia for aeons, it is also suspected to have been the cause of the 1906 San Francisco earthquake.
Millennia ago, when humanity as we know it was a thing still to come, Shudde-M’ell sided with the Great Old Ones in their war against the Elder Gods. When the Great Old Ones were bested, the Elder Gods imprisoned their defeated enemies rather than destroy them. As such, Shudde-M'ell found itself locked in a subterranean prison below the sands of Ethiopia, with the Elder Gods using their Star-Stone artefacts to keep them from escaping.
Over the aeons, humans evolved to their present condition, and sprung from the valleys of Africa. With time, tribes of humans reached Ethiopia, and with them came curiosity. The masters of the tribe, those known as shamans, began to excavate the unusual outcroppings that surrounded them, and eventually came across strange artefacts which they chose to wear as badges of office. As time went on, the shamans dug up further artefacts, and the number of these charms worn became a sign of seniority amongst others. Little did these men know how the taking of the star-stones would affect the world around them . . .
As the star-stones were slowly removed, so were their confining properties, and soon the Cthonians were free. With this, Shudde-M'ell and his kind were free to roam the earth, and so they did for the next few millennia, excavating their lairs across the globe and eventually infesting nearly every part of the planet.
Come the 1960's, a group of humans known as the Wilmarth Foundation became aware of these creatures and began to plot ways to rid the planet of their foul taint. In conjunction with noted occultists Titus Crow and Henri-Laurent de Marigny, they launched simultaneous campaigns known as the Great Britain Project and the American Project which were ultimately successful in driving the bulk of the Cthonians from their respective domains.
Heady from the successes of the Projects, the Foundation attempted to lure in and destroy Shudde-M'ell itself with the most lethally radioactive of materials. Sending an expedition to Africa, the Foundation discovered that they had underestimated the power of their enemy, and whilst Shudde-M'ell was grievously injured by the assault, it fled, burrowing deep into the planet, and escaping through the molten magma beneath the Earths' crust. The Foundation, in return, lost all of its' equipment, and every member of the expedition bar one, a telepath who only lived long enough to tell of his groups demise.
This event caused the Wilmarth Foundation to reconsider whether it was actually possible to kill entities such as Shudde-M'ell; if it was, they reasoned, then why would the Elder Gods, beings of unimaginable power, option to imprison and not simply annihilate them?