While Wyverns, Drakes, and True Dragons rule over most of the world, there is one place where a different branch of the draconic family manages to thrive in their absence. That place is this isolated continent of Uluria and its draconic rulers are the Wyrms.
The Wyrms can be differentiated from snakes by their jaw anatomy, armored scales, intelligence, and elemental abilities. While not as intelligent as humans or true dragons, Wyrms are capable of complex thoughts at around the same level as a crow or parrot... only that they are much more dangerous than said birds (and 100% predatory).
Terrestrial Wyrms have been outcompeted by their winged and legged relatives in most parts of the world, with smaller species finding refuge in small, tropical islands that don't have enough resources to support larger creatures. On Uluria, however, they've diversified into a multitude of species, which include some truly giant forms.

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The Wyrm King is the most powerful species of Wyrm known to inhabit Uluria. It usually inhabits rocky and mountainous areas that allow it to easily set up ambushes on unsuspecting prey. Once the target is in sight, the Wyrm King will unleash a torrent of super-heated flames in order to kill it. It will then drag its prey into a quiet area and leisurely feed on it by ripping chunks of flesh off with its jaws, all the while keeping its meal in place by coiling around it.
If it feels threatened or surprised by something it is unfamiliar with, it will raise its body and hiss loudly in a threatening manner. Wyrm Kings typically don't like wasting their fire and energy on fighting off potential threats; they prefer to avoid needless conflicts if possible.

As of yet, there have been no humanoid fatalities caused by Wyrm Kings. The working theory is that it's due to the fact that so far these draconic serpents are yet to determine if it is worth preying on humanoids or not.