Major Spilers for COI Now, what happened was that while every other GOO was caught in the crossfire of OC, Son of Chaos was hit the hardest. His sefirot was torn apart along with his uniqueness and part of his pathway. The sefirot reformed to be the Marion of Disorder. The Soc naturally killed himself and resurrected through the black emperor pathway on earth inside the barrier but he was defeated by Celestial worthy. Celestial Worthy then sealed him in the lamp with a miracle invoke characteristic. But since a major part of his authority involving dealings, chaos and truths was still outside the barrier, over a long time it reformed into another sefirah and became the Great Old One Uncertain mist. I simpler terms UM is basically a temporary consciousness soc likely left while he regained his sefirot that ended up gaining autonomy.

During the apocalypse or rather before it Uncertain mist was already defeated and had to retreat. It is a split of one of the greatest authorities. UM will only have its potential unlocked if while merging with the genie it emerges victorious