Chasmfiend
A chasmfiend is an enormous predatory creature native to the Shattered Plains and surrounding regions of Roshar in Brandon Sanderson's The Stormlight Archive. Among the largest of the greatshells, chasmfiends are central to the economy and warfare of the Shattered Plains.
Description
Chasmfiends are massive crustacean-like greatshells, with hardened carapace, multiple legs, and great claws. Like other Rosharan greatshells, they are far larger than ordinary biology would permit, sustained in part by a symbiotic bond with spren that helps support their enormous bulk. They dwell in the deep chasms that crisscross the Shattered Plains, emerging at intervals.
Chrysalises and gemhearts
Periodically, chasmfiends climb onto the plateaus of the Shattered Plains to pupate, encasing themselves in a great chrysalis. Within the chrysalis grows a gemheart, a large and valuable gemstone. These gemhearts are immensely prized, both for their worth and for their use in Soulcasting and fabrials, and the contest to reach and harvest a chrysalis before it hatches or before a rival army arrives drives much of the plateau warfare between the Alethi and the listeners.
Role in the story
The hunting of chasmfiends and the race for their gemhearts shape the military campaigns on the Shattered Plains in the early Stormlight Archive. A chasmfiend attack is also among the early dramatic events of the series, demonstrating the danger these creatures pose even to well-armed forces.