Chasmfiends - also known as ulo mas vara to the Parshendi - are massive crustacean-like creatures that dwell within the chasms of the Shattered Plains. They are a type of greatshell and the source of gemhearts (large valuable gemstones), for which they are hunted.
They have a twisted, arrowhead-like face, uniform green eyes and a mouth full of barbed mandibles. The mandibles likely account for the beast's deep, overlapping, trumpeting voices.
Every chasmfiend grows a gemstone inside, called a gemheart. Each gemstone is unusually large and extremely valuable, especially when compared to those of other known greatshells. The chasmfiend's life cycle is complex and, at some point within it, it seeks one of the wider plateaus, climbs up and forms a pupa, waiting for the coming of a highstorm. During that time, they are very vulnerable.
The chrysalis within which the chasmfiend pupates is very like an enormous, oblong rockbud; fifteen feet tall and attached to the uneven stone of the Shattered Plains by something that looks like crem. Plunging a Shardblade into it would kill the pupating creature, but avoid the region with the valuable gemheart.
Spren like small glowing arrows in schools dance around live chasmfiends, and are a source of light. Individual such spren drift away and vanish like small plumes of smoke rising into the air. (Shallan realizes that she recognizes these spren when they dance around the live chasmfiend that she and Kaladin encounter in the chasm into which they fell.)
The war of the Vengeance Pact has largely deteriorated into a contest to determine which highprince will win the most gemhearts. When killed, chasmfiends attract an unknown type of spren, which appears to be silver in color and is similar to a wisp of smoke. They float out of a freshly killed chasmfiend's body. In a symbiotic relationship with the chasmfiend, they are part of what allow the creatures to grow to the size they do with an exoskeleton. (Along with a high-oxygen, lower-gravity world.)
Links with Voidbringers
In a spanreed conversation between Dalinar and Jasnah, Shallan copied a depiction of a Voidbringer in one of Jasnah's books. Adolin thought it was a chasmfiend, although the depiction was not quite right. Dalinar promised to show her a real (dead) one when she came to the Shattered Plains. However, Jasnah thought that the original artist didn't know what a Voidbringer was, so she drew the most horrific thing of which she knew.
In Part Two of The Way of Kings, Dalinar organized a massive hunting party for a chasmfiend on one of the plateaus of the Shattered Plains as a diversion for King Elhokar. The party had a large military escort and numerous spectators, including Highprinces Sadeas and Vamah, the King's Wit, and Dalinar's sons, Adolin and Renarin. The plan was to bait the chasmfiend to surface on a plateau and attack it from a distance with arrows. The hunt went disastrously wrong when it surfaced prematurely and on the same plateau with the spectators. Elhokar recklessly attempted a direct frontal attack, while Sadeas fired arrows with his grandbow to distract it, and Dalinar and Adolin attacked its legs with their Shardblades. Elhokar was thrown from his horse when his saddle strap broke, and Dalinar and Adolin were forced to interrupt their attacks to come to his aid. Dalinar saved Elhokar's life by catching a blow from one of the beast's claws in an extraordinary display of the power of Shardplate. Adolin made the last attack on one of its legs that finally toppled it. Elhokar recovered from his fall, delivered the final killing blow, and claimed the gemheart.
Shallan observes that although it eats carrion, it's got all the equipment to be a predator. What it doesn't appear to have is a reason to be hanging around the chasms after pupating. However, she occupies it by feeding it dead bodies from the bridge collapse.
Kaladin describes the beast as follows:
The beast filled the chasm. Long and narrow, it wasn’t bulbous or bulky, like some small cremlings. It was sinuous, sleek, with that arrowlike face and sharp mandibles.
It was also wrong. Wrong in a way difficult to describe. Big creatures were supposed to be slow and docile, like chulls. Yet this enormous beast moved with ease, its legs up on the sides of the chasm, holding it so that its body barely touched the ground. It ate the corpse of a fallen soldier, grasping the body in smaller claws by its mouth, then ripping it in half with a gruesome bite.
That face was like something from a nightmare. Evil, powerful, almost intelligent.
Kaladin eventually kills it with Shallan's Shardblade by stabbing it through the roof of its mouth and into its brain. Violet ichor exudes from the beast (which smells like wet mold), and eventually covers the both of them. Even so, they harvest from it a massive green gemheart that shines with an inner light. Shallan later lies about the incident to Dalinar, indicating that the creature was dead when they came upon it, and that they could only get the gemheart out because the creature was already half-rotted ... an explanation with which Kaladin complies, though Dalinar does not believe them.
The chrysalis in which a chasmfiend pupates may be part of the living being and not able to be cut by a Shardblade until the pupating beast is killed. (However, Adolin cut a chrysalis from the outside before making his killing blow.) Thus, it seems that chysalises aren't alive so they can be cut by a Shardblade. So, just what constitutes life with regard to what a Shardblade can cut?
It is noted that hair, nails and chitin can be cut by Shardblades, just like clothing. This would imply that chrysalises are, just like in the real world, made of secretions (silk, for example) and not live tissue.
They could be heavily related to the Parshendi, considering they both have blood smelling of mold, a gemheart, and chitinous armor.
Q&A with Brandon
Q. Between the Parshendi and the Alethi harvesting gemhearts, how long has it been since a chasmfiend got to finish pupating?
A. Aha. I wondered if someone would ask that. Much like whaling in our own world, there is a big ecological price building for what is going on here. You are right to worry about this.
Q. What are the smoke-y spren that appear around a dead chasmfiend?
A. They are in a symbiotic relationship with the chasmfiend, and are part of what allow the creatures to grow to the size they do with an exoskeleton. (Along with a high-oxygen, lower-gravity world.)
Q. Have larger land-going greatshells existed above a chasmfiend?
A. Larger than a chasmfiend, the ones out near Reshi can go on land. So yea, it is possible that there are larger ones. They do better in the water, because of how big they are, the high oxygen, low gravity, and symbiotic relationship with the spren allow for mega fauna that is just unrealistically large and just could exist on earth, so yea.
- The Way of Kings, 13. Ten Heartbeats
- The Way of Kings, 12. Unity
- The Way of Kings, 15. The Decoy
- The Way of Kings, 26. Stillness
- Words of Radiance, 70. From A Nightmare
- The Way of Kings, 43. The Wretch
- The Way of Kings, 28. Decision
- Words of Radiance, 68. Bridges
- Words of Radiance, 72. Selfish Reasons
- Words of Radiance, 75. True Glory