Nishoggua the Night Serpent

In star's domain of night I rest,

With dreams’ arrival I am bless'd.

When screams of terror rend mine sleep,

Nishoggua's fangs have sunk in deep

Nishoggua the Night Serpent is one of the primordial Elder Evils, an ancient being in the form of a colossal serpent. More powerful than many gods, the Night Serpent spends eternity devouring the nightmares of mortals and immortals alike in the hope of bringing about the end of the world. Why the Night Serpent wants the world to end is unknown. Some priests of the fey god Dhasa the Seer have written that she finds our reality to be weak, flawed and broken. They say she longs to create a new universe from the ashes of the old.
Nishoggua’s physical form is an enormous 300 foot long serpent. Her slit-pupil eyes are the sickly yellow-black of rotten eggs and her forked tongue flickers incessantly over scaled lips. Her monstrous fangs are coated with the sticky essence of lost dreams. Midnight-black scales cover her colossal hide, serving as the physical embodiment of the terrors and nightmares she has ingested. When she speaks, she speaks with a deep, rich, malignant voice echoing with ancient horror beyond imagining.
The Night Serpent is thought to have been created eons ago in a distant world, when the very first mortal dreamed the very first dream. She has devoured the nightmares of the living ever since. In time even the dreams of the gods began to fall victim to her ravenous appetite.
Clerics of Oryaan believe the Night Serpent was created to be the opposite of what she eats. They say that if the first mortal’s first dream had been a nightmare, Nishoggua would have emerged as a beautiful creature of goodness and light who swallowed pleasant dreams instead of evil ones. Whether that would have been better or worse for the world has been fiercely debated by religious scholars.
Nishoggua has been known by many names throughout the ages. The ancient giants called her Nidhogg, believing she will gnaw the roots of the world forest until it can no longer sustain life. The fey inhabitants of Cernoa call her Maerloch, believing she is the Mother of the Night Parade, a chaotic carnival of darkness and evil (though many say this is not true).
In Chult, Nishoggua is known as the Eater of Worlds. The batiri goblin tribes say the goddess Eshnunna — the Serpent of Wisdom — once banished Nishoggua, though she will one day return. Eshnunna will battle the Night Serpent when she emerges from an iron door beneath the Peaks of Flame and tries to eat the sun. If Eshnunna fails, the stories say Nishoggua ends the world.
Nishoggua-worshipping yuan-ti are said to have colonized ruins deep in the Chultan jungles. Often fanatical cultists, the yuan-ti work to release Nishoggua and bring about the destruction of our universe and the creation of a better one.
The Night Serpent lairs in a vast cavern near an un-named river which crosses the deepest depths of the Plane of Shadow. The rumble of her breathing as she sleeps shakes the ground for miles around, though she is aware of any creature that approaches her cave and immediately wakes to savor their worst nightmares as she devours them.