When Old Souls could still roam the Earth through their dreams, there was a code. Old Souls were not allowed to join with or interfere with other’s dreams. If this went wrong, your soul was damaged and traumatized, rendering the soul broken.
Because of this, the Dream Realm, ruled by Tallulah, was a place to regulate the use of dreams and punish transgressors. She was killed by a man called Ephraim in her Throne Room, who felt he was being unjustly punished for trying to help his traumatized daughter. With Tallulah’s daughter also having disappeared recently, the Dream Domain has fallen into disuse.