In the first Mistborn novel, we are told that the Deepness is a dark entity that the Lord Ruler had defeated at the Well of Ascension. In the second Mistborn novel, however, we learn more about what the Deepness truly is.
We learn that it was dangerous. That it had ravaged the land, slaying thousands. According to Vin, “the monster had sown chaos wherever it stepped, bringing destruction and fear, but the armies of mankind had been unable to defeat it. Only the Terris prophecies and the Hero of Ages had offered any hope” (2.179).
Rumors About the Deepness
There was debate among those who believed the Deepness was real as to what it was. Some held to the Lord Ruler’s official story, that the Deepness was a horrible, supernatural beast, like a dark god. Others think the Deepness was an army of some sort, perhaps invaders from another land. The Farmost Dominance, during pre-Ascension times, was apparently populated with several tribes who were considered primitive and warlike (2.358).
Still others theorized that it was the first attack from the koloss—-this would explain how the Lord Ruler had “gained power” over the Deepness at the Well of Ascension—it may be as simple as he gained the support of the koloss, then used them as his armies (2.359).
Others say the Deepness was the mist—but the mist is obviously still present. And, if it was simply mist, why is it called by such an obscure name?
What is known and heard of the Deepness comes from oral lore, and something common like this can take on mystical properties when transferred verbally through generations. Therefore, Sazed maintains, the Deepness could mean not solely the mist, but the event of its coming or alteration.
Sazed says the problem with this theory is that the Deepness was terrible and destructive and that the mists seem to display none of this danger (2.359). Vin points out, however, that the mists kill people now. Furthermore, it can deplete food stores, and without sunlight, the cops can’t grow, and the animals can’t graze.
So, what is the Deepness after all?
The Deepness Explanation
The Deepness, in reality, is the mists of the world and the effects that Ruin and Preservation have upon it.
Pre-Ascension
Before Rashek took up power at the Well of Ascension, Preservation, the god of preserving life, had used up almost all of his power to imprison Ruin, the god of destruction. Preservation had set up the mists, too. He was deeply afraid of Ruin escaping the prison he had created for him.
In those early days, the mists began to Snap people as they did during the time of the novels—but this action of the mists was one of the only ways to awaken Allomancy in a person, for the genetic attributes were buried too deeply to be brought out by a simple beating, like in the current time. The mists of that day also only created Mistings, because Mistborn were not created until the Lord Ruler created nuggets of Lersarium at the Well of Ascension.
The people misinterpreted the mists’ intent, as the process of Snapping Allomancers caused some—particularly the young and the old—to die. This hadn’t been Preservation’s desire, but he’d given up most of his consciousness to form Ruin’s prison, and the mists had to be left to work as best they could without specific direction.
Ruin, subtle as ever, knew that he couldn’t stop the mists from doing their work. However, he could do the unexpected and encourage them. And so, he helped make them stronger. That brought death to the plants of the world.
So, the mists act upon the whims of two very different gods for very different reasons—they cover the land during the day to destroy the world at Ruin’s behest, and they attack people based on Preservation’s desire to create Mistings. Together, these effects make the mists ominous to the people of this world, and the phenomenon becomes known as The Deepness.
Ascension
Preservation knew that he needed someone to go to the Well of Ascension every thousand of years or so to use the power there and keep Ruin contained within his prison. That’s the true reason Preservation had helped to create the Deepness – to Snap people into becoming Allomancers in the hope that one will hear the pounding at the Well and use the power to keep Ruin in check.
Ruin, meanwhile, was the one responsible for strengthening the mists and manipulating the terris prophecies, making it seem like the Hero of Ages needed to defeat the Deepness by releasing the power at the Well of Ascension. However, this is actually how you free Ruin from his prison, and that’s what he wanted all along.
So, it was good that Rashek got rid of Alendi and took power at the Well of Ascension for himself rather than releasing it—this kept Ruin inside of his prison. The mists return to normal after Rashek takes power at the Well of Ascension, and they only come out during the night, no longer harming anyone. During the Final Empire, Rashek, the Lord Ruler, maintains that he had defeated the Deepness at the Well of Ascension, and no one could refute him, since very few beings were around from those days.
Post-Ascension
After Vin kills the Lord Ruler, however, Preservation must use the mists again to attack people and try to Snap allomancers, preparing them for Ruin’s coming.
The pulses from the Well of Ascension call out to Vin, and Preservation hopes that she will use the power and keep Ruin inside of his prison. Ruin, meanwhile, hopes that she will give up the power and release him.
When Vin arrives at the Well of Ascension, the Mists attack Elend, as Preservation hopes Vin will take up the power in order to save him. However, she nobly gives up the power, because she believes it’s what Elend would have wanted. This is what Ruin has wanted all along, and the god of destruction is finally able to escape his prison.
However, Preservation had a plan prepared for this. The god uses the mists to create an army of allomancers able to resist Ruin and use up all the Atium at the Pits of Hathsin. Atium, as it turns out, is Ruin’s body. By creating an army of Atium mistings, Preservation can effectively weaken Ruin and make an army of allomancers able to resist him.
Harmony
When Rashek (the Lord Ruler) had harnessed the power of the Well of Ascension, he moved the planet closer to the sun in an attempt to burn the Deepness off, but this caused an inhospitably hot planet. In an attempt to fix this, Rashek created the ashmounts (volcanoes) to cool the air. However, with the ashy air now hard to breathe, he had to also grant living beings the ability to inhale ash.
At the end of the novels, Sazed takes up both the power of Ruin and Preservation and becomes Harmony, ultimately balancing the two forces of the gods and blending the intents of both. He moves the planet back into its proper position, and no longer does the world burn too hot because it’s too close to the sun, and no longer does it need ashmounts to cool it off for this reason. The beings of the world no longer need the ability to breathe ash. Green plants and abundant wildlife return to the world, and both gods are kept in check.
