Kashtiliash

Kashtiliash is a fictional entity that appears in the television series Supernatural. It is introduced in the eleventh season as a primordial force of darkness, older than the Darkness itself. Kashtiliash is depicted as a colossal, shadowy creature that resides deep within the Earth, a being of immense power and ancient malice. Its existence is linked to the very fabric of the universe, representing a force that predates creation and seeks to consume all light and life.

The entity is revealed to have been imprisoned by the Archangels millennia ago, its power sealed away to prevent it from plunging the world into eternal night. However, as the Darkness begins to break free, the seals holding Kashtiliash weaken, and its influence starts to seep into the world. Sam and Dean Winchester, the series' protagonists, become aware of Kashtiliash's impending return and the catastrophic threat it poses. They learn that defeating such a primordial entity requires immense sacrifice and a united front of celestial and demonic forces. The entity's ultimate goal is the complete annihilation of all existence, returning the universe to a state of void. Its lore within Supernatural suggests a cosmic struggle between primordial forces of creation and destruction, with Kashtiliash representing the latter.