As Koloss grow, their skin goes from super loose to stretching and breaking.

It was a creature of smaller size—perhaps six feet tall. It was man-shaped, with two arms and legs, though its neck was hard to distinguish. It was completely bald. The oddest feature, however, was its blue skin, which hung loose and folded.


Like... a person wearing a mask made of skin, Sazed thought, trying to push away his disgust. So... their body continues to grow, but their skin doesn't?

His thought was confirmed as a massive, ten-foot-tall beast of a koloss wandered into the group. Smaller creatures scattered before this newcomer, who thumped up to the fire, where several horses were roasting.

This largest creature's skin was pulled so tight it was beginning to tear. The hairless blue flesh had ripped around the eyes, at the edges of the mouth, and around the massive chest muscles. Sazed could see little trails of red blood dripping from the rips. Even where the skin wasn't torn, it was pulled taut—the nose and ears were so flat they were almost indistinguishable from the flesh around them.
Well of Ascension - Chapter 19

They are also fairly violent creatures who fight a lot. Which, of course, damages the skin more.

One of the koloss beside Sazed howled in sudden anger. Sazed spun as the koloss jumped at one of its companions. The creature ignored the sword on its back, instead punching his enemy's head with a blocky fist. The others paused, turning to watch the fight, but none of them seemed alarmed.

Sazed watched with growing horror as the aggressor proceeded to repeatedly pummel his enemy. The defender tried to protect himself, getting out a dagger and managing to score a cut on the aggressor's arm. The blue skin tore, seeping bright red blood, as the aggressor got his hands around his opponent's thick head and twisted.
Well of Ascension - Chapter 19

But Koloss also reuse the skin when creating new Koloss.

Vin rushed ahead, cutting him off just as he reached the tent with the wounded. "Human," she said warily. "What are you doing?"

He ignored her, slamming the dead koloss down on the ground. Now, finally, Human ripped the skin off the corpse. It came off easily—this was one of the smaller koloss, whose skin hung in folds, far too large for its body.

Human pulled the skin free, causing several of the watching guards to groan in disgust.


A spike. A small metal spike driven into the side of the dead koloss. There was a rip of blue skin beside the spikehead, as if...

As if the spikes were holding the skin in place, Vin thought. Like nails holding cloth to a wall.
The Hero of Ages - Chapter 37

(all bolded emphasise mine)

So if the skin is reused, but also extremely prone to damage, where does new skin come from when they need to replace one?

1 Answer 1


You are misunderstanding the text. It's not the skin that is being reused to create new koloss; it's the spikes, which are described in that last quote in your question, that are reused. The koloss removed the other's skin presumably to make it easier to get the spikes.

Koloss are created through hemalurgy, which is the magical art of driving spikes through specific points of the body. The spikes themselves are created by killing another human with the spike, and stealing a specific attribute from them, which imbues the spike with that attribute. These attributes can be one of the allomantic or feruchemical powers, but, though I cannot recall it ever explicitly being stated, I believe it can also be a basic attribute like intelligence or strength as well, as koloss do not seem to possess feruchemy nor allomancy. When the spike is then driven through another living person, that attribute is conferred to that person. Driving the spike through them also may produce various other effects depending on the location, which attribute was in the spike, size, etc.

So, to answer your question, the skin of the koloss is the skin of the human that is made into the koloss. The practice of hemalurgy distorts their bodies when they become Koloss, resulting in their unique skin that does not appear to grow.

It is the same way steel inquisitors and kandra are created, except that a different combination of spike locations, spike materials, spike size, and spike attributes are used, to create different creatures.

  • 1
    I'm familiar with Hemalurgy. Are you postulating that upon completion of the process, the "host" human (for lack of a better term) has their skin turn blue and suddenly grow massive? I'm not convinced. Do you have any references or WoBs that support this?
    – amflare
    Commented Sep 27, 2018 at 13:47
  • I wouldn't say it's postulation, as this is all heavily implied, even if not directly stated in the text, also quote from an author Q&A wob.coppermind.net/events/137-general-signed-books-2015/#e8075
    – Kai
    Commented Sep 27, 2018 at 16:53
  • coppermind.net/wiki/Koloss#cite_note-Arcanum-8075-8 Also, the 17th shard entry - - which is a comprehensive wiki using both text from his books and quotes from Q&As with Brandon Sanderson.
    – Kai
    Commented Sep 27, 2018 at 16:57

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